Modified forms of Pseudomonas exotoxin A

ABSTRACT

Pseudomonas  exotoxin A or “PE” is a 66 kD, highly potent, cytotoxic protein secreted by the bacterium  Pseudomonas aeruginosa . Various forms of PE have been coupled to other proteins, such as antibodies, to generate therapeutically useful cytotoxin conjugates that selectively target cells of a desired phenotype (such as tumor cells). In the present invention, peptides spanning the sequence of an approximately 38 kD form of  Pseudomonas  exotoxin A protein were analyzed for the presence of immunogenic CD4+ T cell epitopes. Six immunogenic T cell epitopes were identified. Residues were identified within each epitope for introduction of targeted amino acid substitutions to reduce or prevent immunogenic T-cell responses in PE molecules which may be administered to a heterologous host.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No. 14/984,006 filed Dec. 30, 2015 (now U.S. Pat. No. 9,447,387), which is a continuation of U.S. application Ser. No. 14/561,707 filed Dec. 5, 2014 (now U.S. Pat. No. 9,371,517), which is a continuation of U.S. application Ser. No. 13/604,173 filed Sep. 5, 2012 (now U.S. Pat. No. 8,932,586), which claims priority benefit of U.S. Application No. 61/531,576 filed Sep. 6, 2011.

REFERENCE TO RELATED APPLICATION

This application claims benefit of and priority based on U.S. Provisional Patent Application Ser. No. 61/531,576, filed Sep. 6, 2011, the contents of which are herein incorporated by reference in their entirety.

NAMES OF THE PARTIES IN A JOINT RESEARCH AGREEMENT

The claimed invention was made pursuant to a joint research agreement, as defined in 35 U.S.C. §103 (c)(3), that was in effect on or before the date the claimed invention was made, and as a result of activities undertaken within the scope of the joint research agreement, by or on behalf of the Intrexon Corp. (Foster City, Calif., U.S.A.) and Antitope Ltd. (Cambridge, UK).

REFERENCE TO SEQUENCE LISTING SUBMITTED ELECTRONICALLY

A Sequence Listing is submitted electronically via EFS-Web as an ASCII formatted sequence listing in a file named “OT050-PCT_SEQLIST.txt”, created on Sep. 4, 2012, and having a file size of 295,678 bytes which is filed concurrently with the present specification, claims, abstract and figures provided herewith. The sequence listing contained in this ASCII formatted document is part of the specification and is herein incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION Immune System and T Cell Epitopes

Immune responses to biological therapeutic agents are wide ranging, and can be directed against agents that are both non-human and human in origin. These responses include those that elicit a weak clinical effect and those that limit efficacy which can occasionally result in morbidity or even mortality in patients. In particular, serious complications can arise with the production of neutralizing antibodies, especially when they target recombinant self proteins and therefore have the potential to cross react with the patient's own endogenous protein (Lim, 2005). Problems associated with immunogenicity to biologies (i.e., therapeutic medical products; such as, antibodies and recombinant proteins/polypeptides) have been reduced largely due to advances in molecular biology. There are, however, many recombinant protein biologies that are identical to endogenously expressed human sequences that still elicit potent neutralizing immune responses in patients (Hochuli, 1997; Schellekens et al, 1997; Namaka et al, 2006). The mechanism by which immunogenicity is triggered remains unclear although the tolerance to self proteins may be broken by a number of factors linked to both the product and the patient (reviewed in Chester et al, 2006; Baker and Jones, 2007). For the product, these include dose, frequency of administration, route, immunomodulatory capacity of the protein therapeutic, and the formulation (Jaber and Baker, 2007). For the patient, factors such as immune competence (i.e. whether the patient is receiving immunosuppressive treatment), patient's MHC haplotype and intrinsic tolerance to the protein therapeutic will influence immunogenicity. Regardless of how immunogenicity is triggered, one of the single most important factors in the development of an ensuing immune response is the presence of epitopes that are able to effectively stimulate a potent CD4+ T cell response (reviewed Baker and Jones, 2007).

T cells or T lymphocytes are a subset of white blood cells known as lymphocytes. (The abbreviation “T” in T cell is for “thymus” since this is the primary organ responsible for T cell maturation.) T cells play a central role in cell-mediated immunity. They can be distinguished from other types of lymphocytes (such as B cells and natural killer cells (NK cells)), by the presence of cell-surface proteins called T cell receptors (TCRs). Different types of T cells have also been identified; these can be distinguished based on the differing functions they serve (e.g., CD4+ T cells (a.k.a., T_(H) or T helper cells), CD8+ cytotoxic T cells (CTLs), memory T cells, regulatory T cells (T_(reg) cells), natural killer cells (NK cells), and gamma delta T cells (γδ T cells)).

T helper (T_(H)) cells are so named because they aid other white blood cells in immunologic processes including, inter alia, assisting the maturation of B cells into plasma and B memory cells, and activation of cytotoxic T cells and macrophages. T_(H) cells are also known as CD4+ T cells because they express CD4 protein on the cell-surface. CD4+ T cells are activated when peptide antigens are presented by MHC class II molecules expressed on the surface of Antigen Presenting Cells (APCs). Once activated, CD4+ T cells divide rapidly and secrete chemokines that further assist in activating or regulating immune responses.

T cell epitope analysis is becoming increasingly important particularly in the pre-clinical analysis of biologies and may, in time, become a requirement for regulatory approval for clinical trials. To this end, a pre-clinical ex vivo T cell assay (EPISCREEN™) has been used to provide an effective technology for predicting T cell immunogenicity by identifying linear T cell epitopes present in protein sequences. Synthetic overlapping peptides typically of about 15 amino acids in length are tested against a cohort of community blood donors carefully selected based on MHC class II haplotypes to provide a quantitative analysis of T cell epitopes present in protein sequences. This technology has been used successfully to compare protein variants for the potential to induce an immune response in vivo. By providing a high degree of sensitivity along with high reproducibility, the EPISCREEN™ assay allows an accurate pre-clinical assessment of the potential for immunogenicity of biologies. See, Baker & Carr, “Preclinical Considerations in the Assessment of Immunogenicity for Protein Therapeutics,” Current Drug Safety 5(4): 1-6 (2010), Bryson et al., “Prediction of Immunogenicity of Therapeutic Proteins: Validity of Computational Tools,” Biodrugs 24(1)1-8 (2010), Holgate & Baker, “Circumventing Immunogenicity in the Development of Therapeutic Antibodies,” IDrugs 12(4):233-237 (2009); Perry et al., “New Approaches to Prediction of Immune Responses to Therapeutic Proteins during Preclinical Development,” Drugs R D 9(6):385-396 (2008); and, Baker & Jones, “Identification and removal of immunogenicity in therapeutic proteins,” Current Opinion in Drug Discovery & Development 10(2):219-227 (2007).

Pseudomonas Exotoxin A

Pseudomonas exotoxin A (PE-A) is a highly potent, 66 kD, cytotoxic protein secreted by the bacterium Pseudomonas aeruginosa. PE-A causes cell death by inhibiting protein synthesis in eukaryotic cells via inactivation of translation elongation factor 2 (EF-2), which is mediated by PE-A catalyzing ADP-ribosylation of EF-2 (i.e., transfer of an ADP ribosyl moiety onto EF-2). PE-A typically produces death by causing liver failure.

PE-A has at least three different structural domains responsible for various biological activities (FIG. 1). See e.g., Siegall et al., Biochemistry, vol. 30, pp. 7154-7159 (1991); Theuer et al., Jour. Biol. Chem., vol. 267, no. 24, pp. 16872-16877 (1992); and, U.S. Pat. No. 5,821,238. PE-A domain IA (amino acids 1-252 (see e.g., SEQ ID NO:133)) is responsible for cell binding. Domain II (amino acids 253-364 (see e.g., SEQ ID NO:133)) is responsible for translocation of PE-A into the cell cytosol. Domain III, the cytotoxic domain (amino acids 400-613 (see e.g., SEQ ID NO:133)), is responsible for ADP ribosylation of Elongation Factor 2 (EF2); which thereby inactivates EF2, subsequently causing cell death. Additionally, a function for domain IB (amino acids 365-399 (SEQ ID NO:139)) has not been established. Indeed, it has been reported that amino acids 365-380 (SEQ ID NO:138) within domain IB can be deleted without producing an identifiable a loss of function. See, Siegall et al., Biochemistry, vol. 30, pp. 7154-7159 (1991).

It has also been reported that PE-A may comprise any one of at least three different carboxy-terminal tails (FIG. 1); these appear to be essential for maintaining or recycling proteins into the endoplasmic reticulum. See, Theuer et al., J. Biol. Chem., vol. 267, no. 24, pp. 16872-16877 (1992); Chaudhary et al., Proc. Natl. Acad. Sci. USA, vol. 87, pp. 308-312 (1990); and, Seetharam et al., Jour. Biol. Chem., vol. 266, 17376-17381 (1991). In particular, in correspondence with the exemplary sequence shown in FIG. 1 (SEQ ID NO:133) these alternative carboxy-terminal tails comprise amino acid sequences:

609-REDLK-613 (SEQ ID NO:135);

609-REDL-612 (SEQ ID NO:136); and

609-KDEL-612 (SEQ ID NO:137).

Variants of PE-A, modified to lack the cell binding domain but coupled to heterologous cell-specific targeting molecules (e.g., antibodies), have been shown to have reduced levels of non-specific toxicity. See e.g., U.S. Pat. No. 4,892,827.

Various forms of PE-A (e.g., truncated/deletion forms with molecular weights of ˜37 kD, 38 kD, 40 kD, et cetera) have been combined with a number of growth factors, antibodies, and other proteins to generate cytotoxins which selectively target cells of a desired phenotype. See, for example:

-   -   Kreitman et al., “Recombinant immunotoxins and other therapies         for relapsed/refractory hairy cell leukemia,” Leuk. Lymphoma.         Suppl. 2:82-86 (June 2011);     -   Itoi et al., “Targeting of locus ceruleus noradrenergic neurons         expressing human interleukin-2 receptor α-subunit in transgenic         mice by a recombinant immunotoxin anti-Tac(Fv)-PE38,” J.         Neurosci., 31(16):6132-6139 (April 2011);     -   Shapira et al., “An immunoconjugate of anti-CD24 and Pseudomonas         exotoxin selectively kills human colorectal tumors in mice,”         Gastroenterology, 140(3):935-946 (March 2011);     -   Kuan et al., “Affinity-matured anti-glycoprotein NMB recombinant         immunotoxins targeting malignant gliomas and melanomas,” Int. J.         Cancer, 129(1):111-21 (July 2011);     -   Hu et al., “Investigation of a plasmid containing a novel         immunotoxin VEGF165-PE38 gene for anti angiogenic therapy in a         malignant glioma model,” Int. J. Cancer, 127(9):2222-2229         (November 2010);     -   Mareeva et al., “A novel composite immunotoxin that suppresses         rabies virus production by the infected cells,” J. Immunol.         Methods, 353(1-2): 78-86 (February 2010);     -   Zielinski et al., “Affitoxin—a novel recombinant, HER2-specific,         anticancer agent for targeted therapy of HER2-positive         tumors,” J. Immunother. 32(8):817-825 (October 2009);     -   Theuer et al., J. Biol. Chem., 267(24):16872-16877 (1992);     -   Pastan et al., “Recombinant toxins for cancer treatment,”         Science, 254:1173-1177(1991);     -   U.S. Pat. No. 5,821,238 (“Recombinant Pseudomonas Exotoxins with         Increased Activity”); and     -   U.S. Pat. No. 4,892,827 (“Recombinant Pseudomonas Exotoxins:         Construction of an Active Immunotoxin with Low Side Effects”).

A significant disadvantage in using PE-A for treatment of disease, however, is that it is a foreign (non-self) protein being introduced into a heterologous host (e.g., a human). Introduction of non-self proteins into heterologous hosts commonly elicits host immune reactions, such as the generation of antibodies (“neutralizing antibodies”) or immune cell reactions (e.g., cytotoxic T cell responses) which are directed at eliminating the non-self protein (i.e., PE-A). Accordingly, it would be advantageous if elements of PE-A (PE-A epitopes) which are recognized and targeted as “non-self” could be removed prior to use of this molecule as a therapeutic agent.

Deimmunization of PE

Some investigators have previously attempted to identify and remove immunogenic determinants from PE-A (i.e., to “deimmunize” PE-A). See, for example:

-   -   Pastan et al., “Immunotoxins with decreased immunogenicity and         improved activity,” Leukemia and Lymphoma, 52(S2):87-90 (June         2011);     -   Onda et al., “Recombinant immunotoxin against B-cell         malignancies with no immunogenicity in mice by removal of B-cell         epitopes,” Proc. Natl. Acad. Sci. USA, 108(14):5742-5747 (April         2011);     -   Hansen et al., “A recombinant immunotoxin targeting CD22 with         low immunogenicity, low nonspecific toxicity, and high antitumor         activity in mice,” J. Immunother. 33(3):297-304 (April 2011);     -   Stish et al., “Design and modification of EGF4KDEL 7Mut, a novel         bispecific ligand-directed toxin, with decreased immunogenicity         and potent anti-mesothelioma activity,” Br. J. Cancer,         101(7):1114-1123 (October 2009);     -   Nagata et al., “Removal of B cell epitopes as a practical         approach for reducing the immunogenicity of foreign         protein-based therapeutics,” Adv. Drug Deliv. Rev.,         61(11):977-985 (September 2009);     -   Onda et al., “An immunotoxin with greatly reduced immunogenicity         by identification and removal of B cell epitopes,” Proc. Natl.         Acad. Sci. USA, 105(32):11311-11316 (August 2008); and     -   Pastan et al, “Mutated Pseudomonas Exotoxins with Reduced         Antigenicity,” U.S. Patent Application No. 2009/0142341.

Despite progress in the area of deimmunization of PE-A, there remains a need for the development of optimized, less immunogenic or non-immunogenic, biologically active forms of this useful cytotoxin. The invention described herein addresses this need.

BRIEF SUMMARY OF THE INVENTION

Peptides spanning the sequence of an approximately 38 kD (predicted molecular weight) form of Pseudomonas exotoxin A protein (SEQ ID NO:1) were analyzed for the presence of immunogenic CD4+ T cell epitopes. A total of 120 overlapping 15 mer peptides spanning this sequence (SEQ ID NO:1), but also including an amino terminal (Gly_(x5)-Ser)_(x2) linker sequence (SEQ ID NO:3) to produce a 359 amino acid Gly-Ser-PE38 polypeptide sequence (SEQ ID NO:2), were tested against a cohort of healthy human donors. CD4+ T cell responses against individual peptides were measured via proliferation assays. Assay data was used to compile a T cell epitope map of the PE38 sequence. Six immunogenic T cell epitopes were identified. Residues were then identified within each of these epitopes for use in targeted amino acid substitutions to reduce or prevent PE38-induced immunogenicity. Reduction or prevention of PE immunogenicity should allow for multiple therapeutic administrations of cytotoxic PE for use, for example, in the targeted destruction of cancer cells in vivo (such as when administered as an immunoconjugate or cell-surface targeted fusion protein).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. Example of a Pseudomonas exotoxin A protein and domains which may be contained therein.

FIG. 2. Comparison of the frequency of donor allotypes expressed in the IEX01 study cohort (n=52) and the world population.

FIGS. 3A & 3B. CD4+ T cell epitope map of IEX01 PE38 sequence using overlapping 15 mer peptides tested against 52 healthy donors. The non-adjusted (FIG. 3A) and adjusted (FIG. 3B) proliferation assay data for the PE38 sequence is shown. Peptides inducing positive (SI≧2.00, p<0.05, including borderline responses) T cell proliferation responses at a frequency above the background response rate (mean positive T cell responses plus SD) contain T cell epitopes (dotted line indicates the background response threshold). KLH induced positive responses in (SI≧2.00, p<0.05) 75% of (non-adjusted) donors.

FIG. 4. Alignment of peptides 50, 52 and 53 showing the predicted HLA-DR core 9 mer binding register. Predicted core 9 mer sequences are bracketed by p1 and p9 anchor residues. Peptides that stimulated positive T cell responses in the adjusted data set are shown. Amino acid numbering (residues 153 and 161) correspond to SEQ ID NO:2 (PE38 of SEQ ID NO:1 plus amino-terminal linker GGGGGSGGGGGS (SEQ ID NO:3)).

FIG. 5. Alignment of peptides 65, 67 and 68 showing one predicted HLA-DR core 9 mer binding register. Predicted core 9 mer sequences are bracketed by p1 and p9 anchor residues. Peptides that stimulated positive T cell responses in the adjusted data set are shown. Amino acid numbering (residues 196 and 204) correspond to SEQ ID NO:2 (PE38 of SEQ ID NO:1 plus amino-terminal linker GGGGGSGGGGGS (SEQ ID NO:3)).

FIG. 6. Alignment of peptides 81 and 82 showing the potential HLA-DR core 9 mer binding register. Predicted core 9 mer sequences are bracketed by p1 and p9 anchor residues. Peptides that stimulated positive T cell responses in the adjusted data set are shown. Amino acid numbering (residues 244 and 252) correspond to SEQ ID NO:2 (PE38 of SEQ ID NO:1 plus amino-terminal linker GGGGGSGGGGGS (SEQ ID NO:3)).

FIG. 7. Alignment of peptides 110 and 111 showing a predicted HLA-DR core 9 mer binding register. Predicted core 9 mer sequences are bracketed by p1 and p9 anchor residues. Peptides that stimulated positive T cell responses in the adjusted data set are shown. Amino acid numbering (residues 333 and 341) correspond to SEQ ID NO:2 (PE38 of SEQ ID NO:1 plus amino-terminal linker GGGGGSGGGGGS (SEQ ID NO:3)).

FIG. 8. Position of CD4+ T cell epitopes within the PE38 sequence. T cell epitopes identified by EPISCREEN™ T cell epitope mapping are shown as shaded bars above the sequence. The frequency of donors responding (SI≧2.00, p<0.05) to each epitope are indicated by the shading of the bars; light grey <10%, mid grey 10-14%; dark grey >=14%. Numbers assigned to each individual donor (that responded to a corresponding epitope) are included within each shaded bar.

FIG. 9. In vivo Transcription/Translation (IVTT) shows that circular plasmid expression vector encoding PE38-IL2 fusion protein was slightly better at inhibiting Luciferase protein synthesis compared to linearized plasmid encoding the same PE38-IL2 fusion protein.

FIG. 10. Luciferase activity measure in counts per second (CPS) in In vitro Transcription/Translation (IVTT) assays of genes encoding either Wild-Type (WT) PE or encoding amino acid substituted PE.

FIG. 11. Analysis of production of cytokines IL-2 and IL-6 stimulated in response to expression of genes encoding either Wild-Type (WT) PE or encoding amino acid substituted PE.

DETAILED DESCRIPTION OF THE INVENTION I. Definitions and Descriptions

Unless specifically indicated otherwise, as used herein the term “PE” or “PE-A” is intended to indicate a polypeptide comprising a cytotoxic polypeptide sequence derived from a wild-type or naturally occurring form of Pseudomonas aeruginosa exotoxin A protein. In addition to cytotoxic polypeptide sequences, PE polypeptides may comprise additional naturally occurring or heterologous polypeptide sequences. Additional naturally occurring polypeptide sequences may include sequences such as are found in full-length Pseudomonas exotoxin A protein, for example, amino acid sequences responsible for cytosolic translocation and cell-specific targeting (as discussed further herein)). Additional heterologous polypeptide sequences may include sequences with which at least a PE cytotoxic polypeptide is fused to impart additional functions or properties. (For example, a PE cytotoxic polypeptide may be fused to antigen binding polypeptide sequences such as an scFv antibody.) Examples of sequences comprising a cytotoxic portion of PE can be found in SEQ ID NO:1 and SEQ ID NO:4 spanning amino acid residues Phe-134 to Lys-347. Examples of sequences comprising a cytotoxic portion of PE can also be found in SEQ ID NO:133 and SEQ ID NO:134 spanning amino acid residues Phe-400 to Lys-613.

As used herein in reference to PE, unless indicated otherwise, a “cytotoxic polypeptide” or “cytotoxic polypeptide sequence” is intended to indicate a polypeptide (or portion thereof) which is capable of inactivating translation elongation factor 2 (EF-2), mediating ADP-ribosylation of EF-2, inhibiting protein synthesis, or inducing cell death. For example, it has been demonstrated that PE domain III, comprised of amino acid residues 400-613 of SEQ ID NO:133, is sufficient to mediate ADP-ribosylation of EF-2 and thereby cause cell death. See, Theuer et al., J. Biol. Chem., vol. 267, no. 24, pp. 16872-16877 (1992) and Hwang et al., Cell, vol. 48, pp. 129-136 (1987).

Cytotoxic polypeptide sequences in the present invention may also comprise alternative carboxy-terminal sequences. See, Theuer et al., Chaudhary et al. and, Seetharam et al. In particular embodiments, examples of carboxy-terminal tails of PE38 in the present invention may comprise sequences as shown in FIG. 1 (SEQ ID NO:133). Hence, exemplary alternative carboxy-terminal tails may comprise amino acid sequences:

-   609-REDLK-613 (SEQ ID NO:135; numbers 609-613 correspond to SEQ ID     NO:133) -   609-REDL-612 (SEQ ID NO:136; numbers 609-612 correspond to SEQ ID     NO:133); and -   609-KDEL-612 (SEQ ID NO:137; numbers 609-612 correspond to SEQ ID     NO:133).

Unless specifically indicated otherwise, as used herein the term “PE38” is intended to indicate a Pseudomonas aeruginosa exotoxin A (PE (or PE-A)) molecule comprising an amino acid sequence as shown in SEQ ID NO:1. The amino acid sequence used to generate peptide sequences referenced in the Examples is shown in SEQ ID NO:2. SEQ ID NO:2 comprises an amino terminal GGGGGSGGGGGS linker sequence (SEQ ID NO:3) fused to the PE38 amino acid sequence of SEQ) ID NO:1. A variant form of PE38 is shown in SEQ ID NO:4. SEQ ID NO:4 differs from SEQ ID NO:1 by comprising a Ser-to-Asn change at position 114, a Ile-to-Val change at position 141, and a Gly-to-Ser change at position 249.

As used herein, unless specifically stated otherwise, “biological activity” in reference to Pseudomonas exotoxin A (PE-A), PE or PE38 is intended to indicate at least one of the biological activities exhibited by naturally occurring forms of the Pseudomonas aeruginosa exotoxin A molecule. These activities include, for example, cell killing or cell cytotoxic activity (a.k.a., cell cytotoxicity), inactivation of translation elongation factor EF-2, ADP-ribosylation of EF-2, and inhibition of protein synthesis. The biological activity of PE and PE38 polypeptides (and modified forms thereof; e.g., PE and PE38 amino acid substituted variants and fusion proteins) can be measured using assays and experiments which are well-known and routinely used by those skilled in the art. Examples of some of these assays and experiments are further described and referenced herein, without limitation, in the Examples sections included herein.

As used herein, the term “having Pseudomonas exotoxin A (PE-A) biological activity” (or “PE biological activity”) is intended to indicate molecules exhibiting about 5% or more of at least one biological activity compared to a corresponding wild-type, naturally occurring, or non-amino acid substituted form of PE or PE-A. In some embodiments, molecules “having Pseudomonas exotoxin A biological activity” (or “PE biological activity”) exhibit 5% or more, about 10% or more, 10% or more, about 15% or more, 15% or more, about 20% or more, 20% or more, about 25% or more, 25% or more, about 30% or more, 30% or more, about 35% or more, 35% or more, about 40% or more, 40% or more, about 45% or more, 45% or more, about 50% or more, 50% or more, about 60% or more, 60% or more, about 70% or more, 70% or more, about 75% or more, 75% or more, about 80% or more, 80% or more, about 85% or more, 85% or more, about 90% or more, 90% or more, about 95% or more, 95% or more, about 100%, or 100% of at least one biological activity compared to a corresponding wild-type, naturally occurring, or non-amino acid substituted forms of PE or PE-A.

As used herein, the term “wild-type” Pseudomonas exotoxin A (PE-A) (or “wild-type” PE) biological activity is intended to indicate at least one or more biological activities exhibited by naturally occurring forms of the Pseudomonas exotoxin A (PE-A) or PE polypeptides. These include, for example, without limitation, activities such as cell killing or cell cytotoxic activity (a.k.a., cell cytotoxicity), inactivation of translation elongation factor EF-2, ADP-ribosylation of EF-2, and inhibition of protein synthesis. Two examples, without limitation, of polypeptide sequences representing “wild-type” or non-amino acid substituted forms of PE-A are shown in SEQ ID NO:133 and SEQ ID NO:134. Two examples, without limitation, of polypeptide sequences representing “wild-type” or non-amino acid substituted forms of PE are shown in SEQ ID NO:1 (PE38) and SEQ ID NO:4 (variant of PE38).

As used or claimed herein the term “a” or “an” in reference to the subsequent recited entity refers to one or more of that entity, for example, “a PE38 antibody” or “a polynucleotide encoding PE38” is understood to indicate one or more PE38 antibody molecules and one or more polynucleotides encoding PE38, not a single PE38 antibody molecule nor a single polynucleotide molecule encoding PE38, respectively. As such, the terms “a” (or “an”), “one or more,” and “at least one” can be used interchangeably herein.

Likewise, as used herein, the term “polypeptide” is intended to encompass a singular “polypeptide” as well as plural “polypeptides,” and refers to a molecule composed of monomers (amino acids) linked by amide bonds (also known as peptide bonds). The term “polypeptide” refers to any chain or chains of two or more amino acids, and does not refer to a specific length of the product. Thus, peptides, dipeptides, tripeptides, oligopeptides, “protein,” “amino acid chain,” or any other term used to refer to a chain or chains of two or more amino acids, are included within the definition of “polypeptide,” and the term “polypeptide” may be used instead of, or interchangeably with any of these terms. The term “polypeptide” is also intended to refer to the products of post-expression modifications of the polypeptide, such as, but without limitation glycosylation, acetylation, phosphorylation, amidation, et cetera. A “polypeptide” unless specifically described otherwise herein, may be derived from a natural biological source or produced by recombinant technology, but is not necessarily translated from a designated nucleic acid sequence. It may be generated in any manner, including by chemical synthesis.

Polypeptides may have a defined three-dimensional structure, although they do not necessarily have such structure. Polypeptides with a defined three-dimensional structure may be referred to as “folded” or having a “tertiary” structure. Polypeptides not configured into a three-dimensional structure, are referred to as unfolded. As used herein, the term glycoprotein refers to a protein coupled to at least one carbohydrate moiety attached to the protein via a covalent bond.

The term “isolated” is intended to indicate a biological component no longer in its naturally occurring milieu. For example, an “isolated polypeptide” or “isolated polynucleotide” is intended to indicate a polypeptide or polynucleotide, respectively, which has been removed from its naturally occurring milieu and which may have been inserted within a non-naturally occurring milieu. By way of example, this would include, without limitation, a polynucleotide which has been removed from a naturally occurring location within a host genome, and subsequently inserted, for example, into an expression vector or inserted into a new host genome location or into the genome of a heterologous host organism. The “isolation” of a polypeptide or polynucleotide, as used herein, requires no particular level of purification. For example, recombinantly produced polypeptides expressed in host cells are considered isolated for purposes of the invention, as are native or recombinant polypeptides which have been separated, fractionated, or partially or substantially purified by any suitable technique.

Polypeptide embodiments also include fragments, derivatives, analogs, variants and fusion proteins; preferably but not necessarily wherein such embodiments retain one or more biological activities associated with a corresponding full-length or naturally occurring polypeptide. Fragments include proteolytic fragments, deletion fragments, and fragments encoded by synthetically or recombinantly produced polynucleotides. Variants may occur naturally or be non-naturally occurring. Non-naturally occurring variants may be produced using art-known mutagenesis techniques. Variant polypeptides may comprise conservative or non-conservative amino acid substitutions, deletions, or additions. Derivatives include, but are not limited to, polypeptides which contain one or more non-naturally occurring amino acids, non-standard amino acids, and amino acid analogs. Polypeptide embodiments may comprise amino acid sequences which are at least 60% identical, at least 70% identical, at least 80% identical, at least 85% identical, at least 90% identical, at least 95% identical, at least 97% identical, at least 98% identical, or at least 99% identical to SEQ ID NO:1.

Unless specifically defined otherwise, the term “polynucleotide” is intended to indicate nucleic acid molecules or constructs as routinely used and understood by those of skill in the art. For example, nucleic acids include, but are not limited to, molecules such as messenger RNA (mRNA), plasmid DNA (pDNA), complementary DNA (cDNA), and genomic DNA (gDNA). A polynucleotide may comprise a conventional phosphodiester bond or a non-conventional bond (e.g., an amide bond, such as found in peptide nucleic acids (PNA)). The terms “polynucleotide” and “nucleic acid” are intended to include embodiments wherein any one or more sequences of polynucleotide or nucleic acid segments are contained, or comprised within, a larger polynucleotide or nucleic acid sequence. For example, but without limitation, and unless stated otherwise to the contrary herein, reference to a nucleic acid such as “a polynucleotide encoding PE38” is intended to include nucleic acids comprising “a polynucleotide encoding PE38” wherein such polynucleotide may also be part of a larger nucleic acid or polynucleotide, such as an expression vector or a polynucleotide/nucleic acid encoding an PE fusion protein.

An “isolated” nucleic acid or polynucleotide is intended a nucleic acid molecule, DNA or RNA, which has been removed from its native environment. For example, a recombinant polynucleotide encoding an antibody contained in a vector is considered isolated for the purposes of the present invention. Further examples of an isolated polynucleotide include recombinant polynucleotides maintained in heterologous host cells or purified (partially or substantially) polynucleotides in solution. Isolated RNA molecules include in vivo or in vitro synthesized RNA molecules; including synthetically produced molecules.

As used herein, a “coding region” is a portion of nucleic acid containing codons which may be translated into amino acids, although “stop codons” (TAG, TGA, or TAA) are not translated into an amino acids, but may also be considered to be part of a coding region. Unless stated otherwise herein, promoters, ribosome binding sites, transcriptional terminators, introns, and the like, are not considered part of a coding region. Two or more coding regions of the present invention can be present in a single polynucleotide construct, e.g., on a single vector, or in separate polynucleotide constructs, e.g., on separate (different) vectors. Furthermore, any vector may contain a single coding region, or may comprise two or more coding regions, e.g., a single vector may separately encode an immunoglobulin heavy-chain variable region and an immunoglobulin light chain variable region. In addition, a vector, polynucleotide, or nucleic acid embodiments may encode heterologous coding regions, either fused or unfused to a nucleic acid encoding a different heterologous polypeptide. Heterologous coding regions include without limitation specialized elements or motifs, such as a secretory signal peptide or a heterologous functional domains.

In certain embodiments, the polynucleotide or nucleic acid is DNA. In the case of DNA, a polynucleotide comprising a nucleic acid which encodes a polypeptide normally may include a promoter and/or other transcription or translation control elements operably associated with one or more coding regions. An operable association is when a coding region for a gene product, e.g., a polypeptide, is associated with one or more regulatory sequences in such a way as to place expression of the gene product under the influence or control of the regulatory sequence(s). Two DNA fragments (such as a polypeptide coding region and a promoter associated therewith) are “operably associated” if induction of promoter function results in the transcription of mRNA encoding the desired gene product. Thus, a promoter region would be operably associated with a nucleic acid encoding a polypeptide if the promoter was capable of effecting transcription of that nucleic acid. Other transcription control elements, besides a promoter, include for example, but without limitation, enhancers, operators, repressors, and transcription termination signals, can be operably associated with the polynucleotide to direct cell-specific transcription. Suitable promoters and other transcription control regions are disclosed herein.

The terms “antibody” and “immunoglobulin” may be used interchangeably herein. An antibody or immunoglobulin comprises at least the antigen-binding elements (e.g., complementarity determining regions or CDRs) of the variable domain of a heavy chain and/or of the variable domain of a light chain. Basic immunoglobulin structures in vertebrate systems are well understood by those of skill in the art. See, e.g., Harlow & Lane, Using Antibodies: A Laboratory Manual, (Cold Spring Harbor Laboratory Press, 1999 (ISBN 0879695447)); see also, Harlow & Lane, Antibodies: A Laboratory Manual, (Cold Spring Harbor Laboratory Press, 2nd ed. 1988). The term “immunoglobulin” or “antibody” comprises various broad classes of antibody molecules, such as, but without limitation, IgG, IgM, IgA IgG, and IgE classes of antibodies; as well as antibody subclasses (isotypes), such as, IgG1, IgG2, IgG3, IgG4, IgA1, et cetera.

Antibodies or antigen-binding fragments, variants, or derivatives thereof of the invention include, but are not limited to, polyclonal, monoclonal, multispecific, human, humanized, primatized, or chimeric antibodies, single chain antibodies, epitope-binding fragments, e.g., Fab, Fab′ and F(ab′)₂, Fd, Fvs, single-chain Fvs (scFv), single-chain antibodies, disulfide-linked Fvs (sdFv), fragments comprising either a VL or VH domain, fragments produced by a Fab expression library, and anti-idiotypic (anti-Id) antibodies.

As used herein, an “epitope” or “antigenic determinant” is the part of a polypeptide, antigen, or molecule that is recognized by the immune system, specifically by antibodies, B cells, or T cells. Epitopes of polypeptide antigens may function as conformational epitopes or linear epitopes. A conformational epitope is comprised of non-linear sections of a target molecule (such as that formed via the tertiary structure of a folded polypeptide). In contrast, amino acids that make up a linear epitope may be comprised of a continuous sequence of amino acids or may be comprised only of particular amino acid residues critical to antibody/B cell/T cell binding.

By “specifically binds,” it is generally meant that an antibody binds to an epitope via its antigen binding domain, and that the binding entails some complementarity between the antigen binding domain and the epitope. According to this definition, an antibody is said to “specifically bind” to an epitope when it binds to that epitope, via its antigen binding domain more readily than it would bind to a random, unrelated epitope. The term “specificity” may be used herein to qualify the relative affinity by which a certain antibody binds to a certain epitope. For example, antibody “A” may be deemed to have a higher specificity for a given epitope than antibody “B,” or antibody “A” may be said to bind to epitope “C” with a higher specificity than it has for related epitope “D.”

By “preferentially binds,” it is meant that the antibody specifically binds to an epitope more readily than it would bind to a related, similar, homologous, or analogous epitope. Thus, an antibody which “preferentially binds” to a given epitope would more likely bind to that epitope than to a related epitope, even though such an antibody may cross-react with the related epitope.

An antibody is said to competitively inhibit binding of a reference antibody to a given epitope if it preferentially binds to that epitope to the extent that it blocks, to some degree, binding of the reference antibody to the epitope. Competitive inhibition may be determined by any method known in the art, for example, competition ELISA assays. An antibody may be said to competitively inhibit binding of the reference antibody to a given epitope by at least 90%, at least 80%, at least 70%, at least 60%, or at least 50%.

As used herein, the term “affinity” refers to a measure of the strength of the binding of an individual epitope with the CDR of an immunoglobulin molecule. See, e.g., Harlow et al., Antibodies: A Laboratory Manual, (Cold Spring Harbor Laboratory Press, 2nd ed, 1988) at pages 27-28. As used herein, the term “avidity” refers to the overall stability of the complex between a population of immunoglobulins and an antigen, that is, the functional combining strength of an immunoglobulin mixture with the antigen. See, e.g., Harlow at pages 29-34. Avidity is related to both the affinity of individual immunoglobulin molecules in the population with specific epitopes, and also the valencies of the immunoglobulins and the antigen. For example, the interaction between a bivalent monoclonal antibody and an antigen with a highly repeating epitope structure, such as a polymer, would be one of high avidity.

The term “cross-reactivity” refers to the ability of an antibody, specific for one antigen, to react with a second antigen; a measure of relatedness between two different antigenic substances. Thus, an antibody is cross reactive if it binds to an epitope other than the one that induced its formation. The cross reactive epitope generally contains many of the same complementary structural features as the inducing epitope, and in some cases, may actually fit better than the original.

As used herein, the terms “linked,” “fused” or “fusion” may be used interchangeably. These terms refer to the joining together of two more elements or components, by whatever means including chemical conjugation or recombinant means. An “in-frame fusion” refers to the joining of two or more polynucleotide open reading frames (ORFs) to form a continuous longer ORF, in a manner that maintains the correct translational reading frame of the original ORFs. Thus, a recombinant fusion protein is a single protein containing two ore more segments that correspond to polypeptides encoded by the original ORFs (which segments are not normally so joined in nature.) Although the reading frame is thus made continuous throughout the fused segments, the segments may be physically or spatially separated by, for example, in-frame linker sequence. For example, polynucleotides encoding the CDRs of an immunoglobulin variable region may be fused, in-frame, but be separated by a polynucleotide encoding at least one immunoglobulin framework region or additional CDR regions, as long as the “fused” CDRs are co-translated as part of a continuous polypeptide.

In the context of polypeptides, a “linear sequence” or a “sequence” is an order of amino acids in a polypeptide in an amino to carboxyl terminal direction in which residues that neighbor each other in the sequence are contiguous in the primary structure of the polypeptide.

A “variant” of a polypeptide or protein refers to any analogue, fragment, derivative, or mutant which is derived from a polypeptide or protein and which retains at least one biological property of the polypeptide or protein. Different variants of the polypeptide or protein may exist in nature or may be generated artificially (e.g., via synthetic or genetic engineering). Variants may be allelic variations characterized by differences in the nucleotide sequences of the structural gene coding for the protein, or may involve differential splicing or post-translational modification. The skilled artisan can produce variants having single or multiple amino acid substitutions, deletions, additions, or replacements. Variants may include, inter alia: (a) variants in which one or more amino acid residues are substituted with, for example, conservative amino acids, non-conservative amino acids, or amino acid analogs (b) variants in which one or more amino acids are added to the polypeptide or protein, (c) variants in which one or more of the amino acids includes a substituent group, and (d) variants in which the polypeptide or protein is fused with another polypeptide such as serum albumin. The techniques for obtaining these variants, including genetic (suppressions, deletions, mutations, etc.), chemical, and enzymatic techniques, are known to those of skill in the art.

The term “expression” as used herein refers to a process by which a gene produces a biochemical, for example, an RNA or polypeptide. It includes without limitation transcription of the gene into RNA molecules such as, for example, messenger RNA (mRNA), transfer RNA (tRNA) or any other RNA product, and the translation of mRNA into polypeptide(s).

Expression of a gene produces a “gene product.” As used herein, a gene product can be either a nucleic acid, e.g., a messenger RNA produced by transcription of a gene, or a polypeptide which is translated from a transcript. Gene products described herein further include nucleic acids with post transcriptional modifications, e.g., polyadenylation, or polypeptides with post translational modifications, e.g., methylation, glycosylation, the addition of lipids, association with other protein subunits, proteolytic cleavage, et cetera.

As used herein, the term “gene” refers to a polynucleotide comprising nucleotides that encode a functional molecule, including functional molecules produced by transcription only (e.g., a bioactive RNA species) or by transcription and translation (e.g. a polypeptide). The term “gene” encompasses cDNA and genomic DNA nucleic acids. “Gene” also refers to a nucleic acid fragment that expresses a specific RNA, protein or polypeptide, including regulatory sequences preceding (5′ non-coding sequences) and following (3′ non-coding sequences) the coding sequence. “Native gene” refers to a gene as found in nature with its own regulatory sequences. “Chimeric gene” refers to any gene that is not a native gene, comprising regulatory and/or coding sequences that are not found together in nature. Accordingly, a chimeric gene may comprise regulatory sequences and coding sequences that are derived from different sources, or regulatory sequences and coding sequences derived from the same source, but arranged in a manner different than that found in nature. A chimeric gene may comprise coding sequences derived from different sources and/or regulatory sequences derived from different sources. “Endogenous gene” refers to a native gene in its natural location in the genome of an organism. A “foreign” gene or “heterologous” gene refers to a gene not normally found in the host organism, but that is introduced into the host organism by gene transfer. Foreign genes can comprise native genes inserted into a non-native organism, or chimeric genes. A “transgene” is a gene that has been introduced into the genome by a transformation procedure.

“RNA transcript” refers to the product resulting from RNA polymerase-catalyzed transcription of a DNA sequence. When the RNA transcript is a perfect complementary copy of the DNA sequence, it is referred to as the primary transcript or it may be a RNA sequence derived from post-transcriptional processing of the primary transcript and is referred to as the mature RNA, “Messenger RNA (mRNA)” refers to the RNA that is without introns and that can be translated into protein by the cell. “cDNA” refers to a double-stranded DNA that is complementary to and derived from mRNA. “Sense” RNA refers to RNA transcript that includes the mRNA and so can be translated into protein by the cell. “Antisense RNA” refers to a RNA transcript that is complementary to all or part of a target primary transcript or mRNA and that blocks the expression of a target gene. The complementarity of an antisense RNA may be with any part of the specific gene transcript, i.e., at the 5′ non-coding sequence, 3′ non-coding sequence, or the coding sequence.

A “vector” refers to any vehicle for the cloning of and/or transfer of a nucleic acid into a host cell. A vector may be a replicon to which another DNA segment may be attached so as to bring about the replication of the attached segment. A “replicon” refers to any genetic element (e.g., plasmid, phage, cosmid, chromosome, virus) that functions as an autonomous unit of DNA replication in vivo, i.e., capable of replication under its own control. The term “vector” includes both viral and nonviral vehicles for introducing the nucleic acid into a cell in vitro, ex vivo or in vivo. A large number of vectors known in the art may be used to manipulate nucleic acids, incorporate coding sequences into genes, et cetera. Possible vectors include, for example, plasmids or modified viruses including, for example bacteriophages such as lambda derivatives, or plasmids such as pBR322 or pUC plasmid derivatives, or the Bluescript vector. Another example of vectors that are useful in the present invention is the Ultra Vector™ Production System (Intrexon Corp., Blacksburg, Va.) as described in WO 2007/038276, incorporated by reference herein. For example, the insertion of the DNA fragments corresponding to response elements and promoters into a suitable vector for in vitro and/or in vivo expression of modified forms of PE (and fragments thereof) as described herein (including fusion proteins, conjugates, and otherwise linked forms) can be accomplished by ligating the appropriate DNA fragments into a chosen vector that has complementary cohesive termini. Alternatively, the ends of the DNA molecules may be enzymatically modified or any site may be produced by ligating nucleotide sequences (linkers) into the DNA termini. Such vectors may be engineered to contain selectable marker genes that provide for the selection of cells that have incorporated the marker into the cellular genome. Such markers allow identification and/or selection of host cells that incorporate and express the proteins encoded by the marker.

Viral vectors, and particularly retroviral vectors, have been used in a wide variety of gene delivery applications in cells, as well as living animal subjects. Viral vectors that can be used to express embodiments of the invention described herein include, but are not limited to, retrovirus, adeno-associated virus, pox, baculovirus, vaccinia, herpes simplex, Epstein-Barr, adenovirus, geminivirus, and caulimovirus vectors. Non-viral vectors include plasmids, liposomes, electrically charged lipids (cytofectins), DNA-protein complexes, and biopolymers. In addition to a nucleic acid, a vector may also comprise one or more regulatory regions, and/or selectable markers useful in selecting, measuring, and monitoring nucleic acid transfer results (e.g., monitoring transfer to target or non-target tissues, duration of expression, et cetera).

The term “plasmid” refers to an extra-chromosomal element often carrying a gene that is not part of the central metabolism of the cell, and usually in the form of circular double-stranded DNA molecules. Such elements may be autonomously replicating sequences, genome integrating sequences, phage or nucleotide sequences, linear, circular, or supercoiled, of a single- or double-stranded DNA or RNA, derived from any source, in which a number of nucleotide sequences have been joined or recombined into a unique construction which is capable of introducing a promoter fragment and DNA sequence for a selected gene product along with appropriate 3′ untranslated sequence into a cell.

A “cloning vector” refers to a “replicon,” which is a unit length of a nucleic acid, preferably DNA, that replicates sequentially and which comprises an origin of replication, such as a plasmid, phage or cosmid, to which another nucleic acid segment may be attached so as to bring about the replication of the attached segment. Cloning vectors may be capable of replication in one cell type and expression in another (“shuttle vector”). Cloning vectors may comprise one or more sequences that can be used for selection of cells comprising the vector and/or one or more multiple cloning sites for insertion of sequences of interest. The term “expression vector” refers to a vector, plasmid or vehicle designed to enable the expression of an inserted nucleic acid sequence following transformation into the host. The cloned gene, i.e., the inserted nucleic acid sequence, is usually placed under the control of control elements such as a promoter, a minimal promoter, an enhancer, or the like. Initiation control regions or promoters, which are useful to drive expression of a nucleic acid in the desired host cell are numerous and familiar to those skilled in the art. Virtually any promoter capable of driving expression of these genes can be used in an expression vector, including but not limited to, viral promoters, bacterial promoters, animal promoters, mammalian promoters, synthetic promoters, constitutive promoters, tissue specific promoters, pathogenesis or disease related promoters, developmental specific promoters, inducible promoters, light regulated promoters; CYC1, HIS3, GAL1, GAL4, GAL1O, ADH1, PGK, PH05, GAPDH, ADC1, TRP1, URA3, LEU2, ENO, TPI, alkaline phosphatase promoters (useful for expression in Saccharomyces); AOX1 promoter (useful for expression in Pichia); β-lactamase, lac, ara, tet, trp, IP_(L), IP_(R), T7, tac, and trc promoters (useful for expression in Escherichia coli); light regulated-, seed specific-, pollen specific-, ovary specific-, cauliflower mosaic virus 35S, CMV 35S minimal, cassava vein mosaic virus (CsVMV), chlorophyll a/b binding protein, ribulose 1,5-bisphosphate carboxylase, shoot-specific, root specific, chitinase, stress inducible, rice tungro bacilliform virus, plant super-promoter, potato leucine aminopeptidase, nitrate reductase, mannopine synthase, nopaline synthase, ubiquitin, zein protein, and anthocyanin promoters (useful for expression in plant cells); animal and mammalian promoters known in the art including, but are not limited to, the SV40 early (SV40e) promoter region, the promoter contained in the 3′ long terminal repeat (LTR) of Rous sarcoma virus (RSV), the promoters of the E1A or major late promoter (MLP) genes of adenoviruses (Ad), the cytomegalovirus (CMV) early promoter, the herpes simplex virus (HSV) thymidine kinase (TK) promoter, a baculovirus IE1 promoter, an elongation factor 1 alpha (EF1) promoter, a phosphoglycerate kinase (PGK) promoter, a ubiquitin (Ubc) promoter, an albumin promoter, the regulatory sequences of the mouse metallothionein-L promoter and transcriptional control regions, the ubiquitous promoters (HPRT, vimentin, α-actin, tubulin and the like), the promoters of the intermediate filaments (desmin, neurofilaments, keratin, GFAP, and the like), the promoters of therapeutic genes (of the MDR, CFTR or factor VIII type, and the like), pathogenesis or disease related-promoters, and promoters that exhibit tissue specificity and have been utilized in transgenic animals, such as the elastase I gene control region which is active in pancreatic acinar cells; insulin gene control region active in pancreatic beta cells, immunoglobulin gene control region active in lymphoid cells, mouse mammary tumor virus control region active in testicular, breast, lymphoid and mast cells; albumin gene, Apo AI and Apo AII control regions active in liver, alpha-fetoprotein gene control region active in liver, alpha 1-antitrypsin gene control region active in the liver, beta-globin gene control region active in myeloid cells, myelin basic protein gene control region active in oligodendrocyte cells in the brain, myosin light chain-2 gene control region active in skeletal muscle, and gonadotropic releasing hormone gene control region active in the hypothalamus, pyruvate kinase promoter, villin promoter, promoter of the fatty acid binding intestinal protein, promoter of the smooth muscle cell α-actin, and the like. In addition, these expression sequences may be modified by addition of enhancer or regulatory sequences and the like.

Vectors comprising polynucleotides of the invention may be introduced into the desired host cells by methods known in the art, e.g., transfection, electroporation, microinjection, transduction, cell fusion, DEAE dextran, calcium phosphate precipitation, lipofection (lysosome fusion), use of a gene gun, or a DNA vector transporter (see, e.g., Wu et al, J. Biol. Chem. 267:963 (1992); Wu et al, J. Biol. Chem. 263:14621 (1988); and Hartmut et al, Canadian Patent No. 2,012,311).

Vectors and polynucleotides of the invention may be introduced in vivo by lipofection. For example, via use of liposomes for encapsulation and transfection of nucleic acids in vitro. Synthetic cationic lipids designed to limit the difficulties encountered with liposome-mediated transfection can be used to prepare liposomes for in vivo transfection of a gene encoding a marker (Feigner et al, Proc. Natl. Acad. Sci USA. 84:7413 (1987); Mackey et al, Proc. Natl. Acad. Sci USA 85:8027 (1988); and Ulmer et al, Science 259:1745 (1993)). Use of cationic lipids may promote encapsulation of negatively charged nucleic acids, and also promote fusion with negatively charged cell membranes (Feigner et al, Science 337:387 (1989)). Particularly useful lipid compounds and compositions for transfer of nucleic acids are described in WO95/18863, WO96/17823 and U.S. Pat. No. 5,459,127.

Other molecules are also useful for facilitating transfection of a nucleic acid in vivo, such as a cationic oligopeptide (e.g., WO95/21931), peptides derived from DNA binding proteins (e.g., WO96/25508), or a cationic polymer (e.g., WO95/21931).

It is also possible to introduce a vector in vivo as a naked DNA plasmid (see U.S. Pat. Nos. 5,693,622, 5,589,466 and 5,580,859). Receptor-mediated DNA delivery approaches can also be used (Curiel et al., Hum. Gene Ther. 3:147 (1992); and Wu et al., J. Biol. Chem. 262:4429 (1987)).

The term “transfection” refers to the uptake of exogenous or heterologous RNA or DNA by a cell. A cell has been “transfected” by exogenous or heterologous RNA or DNA when such RNA or DNA has been introduced inside the cell.

“Transformation” refers to the transfer of a nucleic acid fragment into the genome of a host organism, resulting in genetically stable inheritance. Host organisms containing the transformed nucleic acid fragments are referred to as “transgenic” or “recombinant” or “transformed” organisms.

In addition, recombinant vector comprising polynucleotides of the invention may include one or more origins for replication in the cellular hosts in which their amplification or their expression is sought, markers or selectable markers.

The term “selectable marker” refers to an identifying factor, usually an antibiotic or chemical resistance gene, that is able to be selected for based upon the marker gene's effect, i.e., resistance to an antibiotic, resistance to a herbicide, colorimetric markers, enzymes, fluorescent markers, and the like, wherein the effect is used to track the inheritance of a nucleic acid of interest and/or to identify a cell or organism that has inherited the nucleic acid of interest. Examples of selectable marker genes known and used in the art include: genes providing resistance to ampicillin, streptomycin, gentamycin, kanamycin, hygromycin, bialaphos herbicide, sulfonamide, and the like; and genes that are used as phenotypic markers, i.e., anthocyanin regulatory genes, isopentanyl transferase gene, and the like.

The term “reporter gene” refers to a nucleic acid encoding an identifying factor that is able to be identified based upon the reporter gene's effect, wherein the effect is used to track the inheritance of a nucleic acid of interest, to identify a cell or organism that has inherited the nucleic acid of interest, and/or to measure gene expression induction or transcription. Examples of reporter genes known and used in the art include: Luciferase (Luc), green fluorescent protein (GFP), chloramphenicol acetyltransferase (CAT), β-galactosidase (LacZ), β-glucuronidase (Gus), and the like. Selectable marker genes may also be considered reporter genes.

“Promoter and “promoter sequence” are used interchangeably and refer to a DNA sequence capable of controlling the expression of a coding sequence or functional RNA. In general, a coding sequence is located 3′ to a promoter sequence. Promoters may be derived in their entirety from a native gene, or be composed of different elements derived from different promoters found in nature, or even comprise synthetic DNA segments. It is understood by those skilled in the art that different promoters may direct the expression of a gene in different tissues or cell types, or at different stages of development, or in response to different environmental or physiological conditions. Promoters that cause a gene to be expressed in most cell types at most times are commonly referred to as “constitutive promoters.” Promoters that cause a gene to be expressed in a specific cell type are commonly referred to as “cell-specific promoters” or “tissue-specific promoters.” Promoters that cause a gene to be expressed at a specific stage of development or cell differentiation are commonly referred to as “developmentally-specific promoters” or “cell differentiation-specific promoters.” Promoters that are induced and cause a gene to be expressed following exposure or treatment of the cell with an agent, biological molecule, chemical, ligand, light, or the like that induces the promoter are commonly referred to as “inducible promoters” or “regulatable promoters.” It is further recognized that since in most cases the exact boundaries of regulatory sequences have not been completely defined, DNA fragments of different lengths may have identical promoter activity.

The promoter sequence is typically bounded at its 3′ terminus by the transcription initiation site and extends upstream (5′ direction) to include the minimum number of bases or elements necessary to initiate transcription at levels detectable above background. Within the promoter sequence will be found a transcription initiation site (conveniently defined for example, by mapping with nuclease S1), as well as protein binding domains (consensus sequences) responsible for the binding of RNA polymerase.

A coding sequence is “under the control” of transcriptional and translational control sequences in a cell when RNA polymerase transcribes the coding sequence into mRNA, which is then trans-RNA spliced (if the coding sequence contains nitrons) and translated into the protein encoded by the coding sequence.

“Transcriptional and translational control sequences” refer to DNA regulatory sequences, such as promoters, enhancers, terminators, and the like, that provide for the expression of a coding sequence in a host cell. In eukaryotic cells, polyadenylation signals are control sequences.

The term “response element” (“RE”) refers to one or more cis-acting DNA elements which confer responsiveness on a promoter mediated through interaction with the DNA-binding domains of a transcription factor. This DNA element may be either palindromic (perfect or imperfect) in its sequence or composed of sequence motifs or half sites separated by a variable number of nucleotides. The half sites can be similar or identical and arranged as either direct or inverted repeats or as a single half site or multimers of adjacent half sites in tandem. The response element may comprise a minimal promoter isolated from different organisms depending upon the nature of the cell or organism into which the response element will be incorporated. The DNA binding domain of the transcription factor binds, in the presence or absence of a ligand, to the DNA sequence of a response element to initiate or suppress transcription of downstream gene(s) under the regulation of this response element. Examples of DNA sequences for response elements of the natural ecdysone receptor include: RRGG/TTCANTGAC/ACYY (SEQ ID NO:140) (see Cherbas et. al., Genes Dev. 5:120-131 (1991)); AGGTCAN(n)AGGTCA (SEQ ID NO:141), where N(n) can be one or more spacer nucleotides (see D'Avino et al., Mol. Cell. Endocrinol. 113:1 (1995)); and GGGTTGAATGAATTT (SEQ ID NO:142) (see Antoniewski et al., Mol. Cell Biol. 14:4465 (1994)).

The terms “operably linked,” “operably associated,” “through operable association,” and the like refer to the association of nucleic acid sequences on a single nucleic acid fragment so that the function of one is affected by the other. For example, a promoter is operably linked with a coding sequence when it is capable of affecting the expression of that coding sequence (i.e., that the coding sequence is under the transcriptional control of the promoter). Coding sequences can be operably linked to regulatory sequences in sense or antisense orientation.

The terms “cassette,” “expression cassette” and “gene expression cassette” refer to a segment of DNA that can be inserted into a nucleic acid or polynucleotide at specific restriction sites or by homologous recombination. The segment of DNA comprises a polynucleotide that encodes a polypeptide of interest, and the cassette and restriction sites are designed to ensure insertion of the cassette in the proper reading frame for transcription and translation. “Transformation cassette” refers to a specific vector comprising a polynucleotide that encodes a polypeptide of interest and having elements in addition to the polynucleotide that facilitate transformation of a particular host cell. Cassettes, expression cassettes, gene expression cassettes and transformation cassettes of the invention may also comprise elements that allow for enhanced expression of a polynucleotide encoding a polypeptide of interest in a host cell. These elements may include, but are not limited to: a promoter, a minimal promoter, an enhancer, a response element, a terminator sequence, a polyadenylation sequence, and the like.

For purposes of expressing polynucleotides and polypeptides under control of a gene switch mechanism, the term “gene switch” refers to the combination of a response element associated with a promoter, and a ligand-dependent transcription factor-based system which, in the presence of one or more ligands, modulates the expression of a gene into which the response element and promoter are incorporated. Stated otherwise, a “gene switch” refers to a peptide, protein or polypeptide complex that functions to (a) bind an activating ligand, and (b) regulate the transcription of a gene of interest in a ligand-dependent fashion.

As used herein with respect to gene switch regulation systems, the term “dimerizes with the ligand binding domain that binds an activating ligand” refers to a selective protein-protein interaction that is induced by the presence of activating ligand.

As used herein, the term “ligand binding domain that binds an activating ligand” refers to an amino acid sequence that selectively binds an activating ligand. In the methods disclosed herein, an activating ligand binds to a ligand binding domain, e.g., an ecdysone receptor ligand binding domain, that is part of a ligand-dependent transcriptional activation complex that regulates the expression of a polynucleotide sequence that encodes a gene of interest. Hence, the expression of the gene of interest is regulated in a ligand-dependent fashion.

The term “ecdysone receptor-based,” with respect to a gene switch, refers to a gene switch comprising at least a functional part of a naturally occurring or synthetic ecdysone receptor ligand binding domain and which regulates gene expression in response to a ligand that binds to the ecdysone receptor ligand binding domain.

The terms “modulate” and “modulates” mean to induce, reduce or inhibit nucleic acid or gene expression, resulting in the respective induction, reduction or inhibition of protein or polypeptide production.

Polynucleotides or vectors comprising sequences encoding polypeptides of the present invention may further comprise at least one promoter suitable for driving expression of a gene in a modified cell.

Enhancers that may be used in embodiments of the invention include but are not limited to: an SV40 enhancer, a cytomegalovirus (CMV) enhancer, an elongation factor 1 (EF1) enhancer, yeast enhancers, viral gene enhancers, et cetera.

“Regulatory region” refers to a nucleic acid sequence that regulates the expression of a second nucleic acid sequence. A regulatory region may include sequences which are naturally responsible for expressing a particular nucleic acid (a homologous region) or may include sequences of a different origin that are responsible for expressing different proteins or even synthetic proteins (a heterologous region). In particular, the sequences can be sequences of prokaryotic, eukaryotic, or viral genes or derived sequences that stimulate or repress transcription of a gene in a specific or non-specific manner and in an inducible or non-inducible manner. Regulatory regions include origins of replication, RNA splice sites, promoters, enhancers, transcriptional termination sequences, and signal sequences which direct the polypeptide into the secretory pathways of the target cell.

The term “exogenous gene” or “heterologous gene” means a gene foreign to the subject or organism, that is, a gene which is introduced into the subject through a transformation process, an unmutated version of an endogenous mutated gene or a mutated version of an endogenous unmutated gene. The method of transformation is not critical to this invention and may be any method suitable for the subject known to those in the art. Exogenous genes can be either natural or synthetic genes which are introduced into the subject in the form of DNA or RNA which may function through a DNA intermediate such as by reverse transcriptase. Such genes can be introduced into target cells, directly introduced into the subject, or indirectly introduced by the transfer of transformed cells into the subject.

Polynucleotides and polypeptides of the invention may be expressed in vivo under control of a “gene switch” control mechanism, such as those described in, for example, but not limited to:

-   -   WO 2009/045370 (PCT/US2008/011270);     -   WO 2009/025866 (PCT/US2008/010040);     -   WO 2008/073154 (PCT/US2007/016747);     -   WO 2005/108617 (PCT/US2005/015089);     -   WO 2003/0/27289 (PCT/US2002/005026);     -   WO 2002/066615 (PCT/US2002/005708);     -   WO 2003/027266 (PCT/US/2002/05234);     -   WO 2002/066612 (PCT/US2002/005090);     -   WO 2002/066614 (PCT/US/2002/005706);     -   WO 2002/066613 (PCT/US2002/005090);     -   WO 2002/029075 (PCT/US2001/030608); and     -   WO 2001/070816 (PCT/US2001/090500),         each of which are incorporated by reference herein.

The term “ligand-dependent transcription factor complex” or “LDTFC” refers to a transcription factor comprising one or more protein subunits, which complex can regulate gene expression driven by a “factor-regulated promoter” as defined herein. A model LDTFC is an “ecdysone receptor complex” generally refers to a heterodimeric protein complex having at least two members of the nuclear receptor family, ecdysone receptor (“EcR”) and ultraspiracle (“USP”) proteins (see Yao et al., Nature 366:476 (1993)); Yao et al., Cell 71:63 (1992)). A functional LDTFC such as an EcR complex may also include additional protein(s) such as immunophilins. Additional members of the nuclear receptor family of proteins, known as transcriptional factors (such as DHR38, betaFTZ-1 or other insect homologs), may also be ligand dependent or independent partners for EcR and/or USP. A LDTFC such as an EcR complex can also be a heterodimer of EcR protein and the vertebrate homolog of ultraspiracle protein, retinoic acid-X-receptor (“RXR”) protein or a chimera of USP and RXR. The terms “LDTFC” and “EcR complex” also encompass homodimer complexes of the EcR protein or USP, as well as single polypeptides or tamers, tetramer, and other multimers serving the same function.

A LDTFC such as an EcR complex can be activated by an active ecdysteroid or non-steroidal ligand bound to one of the proteins of the complex, inclusive of EcR, but not excluding other proteins of the complex. As used herein, the term “ligand,” as applied to LDTFC-based gene switches e.g., EcD complex based gene switches, describes small and soluble molecules having the capability of activating a gene switch to stimulate expression of a polypeptide encoded therein. Examples of ligands include, without limitation, an ecdysteroid, such as ecdysone, 20-hydroxyecdysone, ponasterone A, muristerone A, and the like, 9-cis-retinoic acid, synthetic analogs of retinoic acid, N,N′-diacylhydrazines such as those disclosed in U.S. Pat. Nos. 6,013,836, 5,117,057; 5,530,028; 5,378,726, and 7,304,161 and U.S. Pat. No. 7,456,315; oxadiazolines as described in U.S. Pat. No. 7,304,162; dibenzoylalkyl cyanohydrazines such as those disclosed in European Patent No. 461,809B1; N-alkyl-N,N′-diaroylhydrazines such as those disclosed in U.S. Pat. No. 5,225,443; N-acyl-N-alkylcarbonylhydrazines such as those disclosed in European Patent No. 234,99481; N-aroyl-N-alkyl-N′-aroylhydrazines such as those described in U.S. Pat. No. 4,985,461; amidoketones such as those described in U.S. Pat. No. 7,375,093; each of which is incorporated herein by reference and other similar materials including 3,5-di-tert-butyl-4-hydroxy-N-isobutyl-benzamide, 8-O-acetylharpagide, oxysterols, 22(R) hydroxy cholesterol, 24(S) hydroxycholesterol, 25-epoxycholesterol, T0901317, 5-alpha-6-alpha-epoxycholesterol-3-sulfate (ECHS), 7-ketocholesterol-3-sulfate, famesol, bile acids, 1,1-biphosphonate esters, juvenile hormone III, and the like. Examples of diacylhydrazine ligands useful in the present invention include RG-115819 (3,5-Dimethyl-benzoic acid N-(1-ethyl-2,2-dimethyl-propyl)-N′-(2-methyl-3-methoxy-benzoyl)-hydrazide), RG-115932 ((R)-3,5-Dimethyl-benzoic acid N-(1-tert-butyl-butyl)-N′-(2-ethyl-3-methoxy-benzoyl)-hydrazide), and RG-115830 (3,5-Dimethyl-benzoic acid N-(1-tert-butyl-butyl)-N′-(2-ethyl-3-methoxy-benzoyl)-hydrazide). See, e.g., U.S. Pat. No. 8,076,517 (Publication No. 2009/0163592), and PCT Appl. No. PCT/US2008/006757 (WO 2008/153801), both of which are incorporated herein by reference in their entireties.

A LDTFC such as an EcR complex includes proteins which are members of the nuclear receptor superfamily wherein all members are characterized by the presence of one or more polypeptide subunits comprising an amino-terminal transactivation domain (“AD,” “TD,” or “TA,” used interchangeably herein), a DNA binding domain (“DBD”), and a ligand binding domain (“LBD”). The AD may be present as a fusion with a “heterodimerization partner” or “HP.” A fusion protein comprising an AD and HP of the invention is referred to herein as a “coactivation protein” or “CAP.” The DBD and LBD may be expressed as a fusion protein, referred to herein as a “ligand-inducible transcription factor (“LTF”). The fusion partners may be separated by a linker, e.g., a hinge region. Some members of the LTF family may also have another transactivation domain on the carboxy-terminal side of the LBD. The DBD is characterized by the presence of two cysteine zinc fingers between which are two amino acid motifs, the P-box and the D-box, which confer specificity for ecdysone response elements. These domains may be either native, modified, or chimeras of different domains of heterologous receptor proteins.

EcR ligands, when used with a LDTFC, e.g., an EcR complex, which in turn is bound to the response element linked to an exogenous gene (e.g., a reporter gene), provide the means for external temporal regulation of expression of the exogenous gene. The order in which the various components bind to each other, that is, ligand to receptor complex and receptor complex to response element, is not critical. Typically, modulation of expression of the exogenous gene is in response to the binding of a LDTFC, e.g., an EcR complex, to a specific control, or regulatory, DNA element. The EcR protein, like other members of the nuclear receptor family, possesses at least three domains, an AD, a DBD, and a LBD. This receptor, like a subset of the nuclear receptor family, also possesses less well-defined regions responsible for heterodimerization properties (referred to herein as a “heterodimerization partner” or “HP”). Binding of the ligand to the ligand binding domain of a LTF, e.g., an EcR protein, after heterodimerization with a CAP including, e.g., an AD and/or an HP, e.g., a USP or RXR protein, enables the DNA binding domains of the heterodimeric proteins to bind to the response element in an activated form, thus resulting in expression or suppression of the exogenous gene. This mechanism does not exclude the potential for ligand binding to individual subunits, e.g., LTF or CAP, e.g., an EcR or USP, and the resulting formation of active homodimer complexes (e.g. EcR+EcR or USP+USP). In one embodiment, one or more of the receptor domains can be varied producing a chimeric gene switch. Typically, one or more of the three domains may be chosen from a source different than the source of the other domains so that the chimeric receptor is optimized in the chosen host cell or organism for transactivating activity, complementary binding of the ligand, and recognition of a specific response element. In addition, the response element itself can be modified or substituted with response elements for other DNA binding protein domains such as the GAL-4 protein from yeast (see Sadowski et al., Nature 335:563 (1988) or LexA protein from E. coli (see Brent et al., Cell 43:729-736 (1985)) to accommodate chimeric LDTFCs, e.g., EcR complexes. Another advantage of chimeric systems is that they allow choice of a promoter used to drive the exogenous gene according to a desired end result. Such double control can be particularly important in areas of gene therapy, especially when cytotoxic proteins are produced, because both the timing of expression as well as the cells wherein expression occurs can be controlled. When exogenous genes, operatively linked to a suitable promoter, are introduced into the cells of the subject, expression of the exogenous genes is controlled by the presence of the ligand of this invention. Promoters may be constitutively or inducibly regulated or may be tissue-specific (that is, expressed only in a particular type of cell) or specific to certain developmental stages of the organism.

For in vivo use, the ligands described herein may be taken up in pharmaceutically acceptable carriers, such as, for example, solutions, suspensions, tablets, capsules, ointments, elixirs, and injectable compositions. Pharmaceutical compositions may contain from 0.01% to 99% by weight of the ligand. Compositions may be either in single or multiple dose forms. The amount of ligand in any particular pharmaceutical composition will depend upon the effective dose, that is, the dose required to elicit the desired gene expression or suppression.

Suitable routes of administering the pharmaceutical preparations include oral, rectal, topical (including dermal, buccal and sublingual), vaginal, parenteral (including subcutaneous, intramuscular, intravenous, intradermal, intrathecal and epidural) and by nasogastric tube. It will be understood by those skilled in the art that the preferred route of administration will depend upon the condition being treated and may vary with factors such as the condition of the recipient.

As used herein, the terms “treat” or “treatment” refer to both therapeutic treatment and prophylactic or preventative measures, wherein the object is to prevent or slow down (lessen) an undesired physiological change or disorder, such as the development, progression or spread (i.e., metastasis) of cancer. Beneficial or desired clinical results include, but are not limited to, alleviation of symptoms, diminishment of extent of disease, stabilized (i.e., not worsening) state of disease, delay or slowing of disease progression, amelioration or palliation of the disease state, and remission (whether partial or total). “Treatment” can also mean prolonging survival as compared to expected survival if not receiving treatment. Those in need of treatment include those already with the condition or disorder as well as those prone to have the condition or disorder or those in which the condition or disorder is to be prevented.

The terms “subject,” “individual,” “animal,” “patient,” or “mammal,” is meant any subject, particularly a mammalian subject, for whom diagnosis, prognosis, or therapy is desired. Mammalian subjects include, without limitation, humans, domestic animals, farm animals, and zoo, sports, or pet animals such as dogs, cats, guinea pigs, rabbits, rats, mice, horses, cattle, cows, et cetera.

The terms “hyperproliferative disease or disorder” is intended to encompass all neoplastic cell growth and proliferation, whether malignant or benign, including all transformed cells and tissues and all cancerous cells and tissues. Hyperproliferative diseases or disorders include, but are not limited to, precancerous lesions, abnormal cell growths, tumors (whether benign or malignant), “cancer” and other hyperplasias.

The term “cancer” includes, but is not limited to, primary malignant cells or tumors (e.g., those whose cells have not migrated to sites in the subject's body other than the site of the original malignancy or tumor) and secondary malignant cells or tumors (e.g., those arising from metastasis, the migration of malignant cells or tumor cells to secondary sites that are different from the site of the original tumor).

A tumor or tumor tissue may also comprise “tumor-associated non-tumor cells”, e.g., vascular cells which form blood vessels to supply the tumor or tumor tissue. Non-tumor cells may be induced to replicate and develop by tumor cells, for example, the induction of angiogenesis in a tumor or tumor tissue.

Some examples of cancer include, but are not limited to, carcinoma, lymphoma, blastoma, sarcoma, and leukemia or lymphoid malignancies. More particular examples of such cancers are noted below and include: squamous cell cancer (e.g. epithelial squamous cell cancer), lung cancer including small-cell lung cancer, non-small cell lung cancer, adenocarcinoma of the lung and squamous carcinoma of the lung, cancer of the peritoneum, hepatocellular cancer, gastric or stomach cancer including gastrointestinal cancer, pancreatic cancer, glioblastoma, cervical cancer, ovarian cancer, liver cancer, bladder cancer, hepatoma, breast cancer, colon cancer, rectal cancer, colorectal cancer, endometrial cancer or uterine carcinoma, salivary gland carcinoma, kidney or renal cancer, prostate cancer, vulval cancer, thyroid cancer, hepatic carcinoma, as well as head (e.g., brain) and neck cancer.

Other examples of cancers or malignancies include, but are not limited to: Acute Childhood Lymphoblastic Leukemia, Acute Lymphoblastic Leukemia, Acute Lymphocytic Leukemia, Acute Myeloid Leukemia, Adrenocortical Carcinoma, Adult (Primary) Hepatocellular Cancer, Adult (Primary) Liver Cancer, Adult Acute Lymphocytic Leukemia, Adult Acute Myeloid Leukemia, Adult Hodgkin's Disease, Adult Hodgkin's Lymphoma, Adult Lymphocytic Leukemia, Adult Non-Hodgkin's Lymphoma, Adult Primary Liver Cancer, Adult Soft Tissue Sarcoma, AIDS-Related Lymphoma, AIDS-Related Malignancies, Anal Cancer, Astrocytoma, Bile Duct Cancer, Bladder Cancer, Bone Cancer, Brain Stem Glioma, Brain Tumors, Breast Cancer, Cancer of the Renal Pelvis and Ureter, Central Nervous System (Primary) Lymphoma, Central Nervous System Lymphoma, Cerebellar Astrocytoma, Cerebral Astrocytoma, Cervical Cancer, Childhood (Primary) Hepatocellular Cancer, Childhood (Primary) Liver Cancer, Childhood Acute Lymphoblastic Leukemia, Childhood Acute Myeloid Leukemia, Childhood Brain Stem Glioma, Childhood Cerebellar Astrocytoma, Childhood Cerebral Astrocytoma, Childhood Extracranial Germ Cell Tumors, Childhood Hodgkin's Disease, Childhood Hodgkin's Lymphoma, Childhood Hypothalamic and Visual Pathway Glioma, Childhood Lymphoblastic Leukemia, Childhood Medulloblastoma, Childhood Non-Hodgkin's Lymphoma, Childhood Pineal and Supratentorial Primitive Neuroectodermal Tumors, Childhood Primary Liver Cancer, Childhood Rhabdomyosarcoma, Childhood Soft Tissue Sarcoma, Childhood Visual Pathway and Hypothalamic Glioma, Chronic Lymphocytic Leukemia, Chronic Myelogenous Leukemia, Colon Cancer, Cutaneous T cell Lymphoma, Endocrine Pancreas Islet Cell Carcinoma, Endometrial Cancer, Ependymoma, Epithelial Cancer, Esophageal Cancer, Ewing's Sarcoma and Related Tumors, Exocrine Pancreatic Cancer, Extracranial Germ Cell Tumor, Extragonadal Germ Cell Tumor, Extrahepatic Bile Duct Cancer, Eye Cancer, Female Breast Cancer, Gaucher's Disease, Gallbladder Cancer, Gastric Cancer, Gastrointestinal Carcinoid Tumor, Gastrointestinal Tumors, Germ Cell Tumors, Gestational Trophoblastic Tumor, Hairy Cell Leukemia, Head and Neck Cancer, Hepatocellular Cancer, Hodgkin's Disease, Hodgkin's Lymphoma, Hypergammaglobulinemia, Hypopharyngeal Cancer, Intestinal Cancers, Intraocular Melanoma, Islet Cell Carcinoma, Islet Cell Pancreatic Cancer, Kaposi's Sarcoma, Kidney Cancer, Laryngeal Cancer, Lip and Oral Cavity Cancer, Liver Cancer, Lung Cancer, Lymphoproliferative Disorders, Macroglobulinemia, Male Breast Cancer, Malignant Mesothelioma, Malignant Thymoma, Medulloblastoma, Melanoma, Mesothelioma, Metastatic Occult Primary Squamous Neck Cancer, Metastatic Primary Squamous Neck Cancer, Metastatic Squamous Neck Cancer, Multiple Myeloma, Multiple Myeloma/Plasma Cell Neoplasm, Myelodysplastic Syndrome, Myelogenous Leukemia, Myeloid Leukemia, Myeloproliferative Disorders, Nasal Cavity and Paranasal Sinus Cancer, Nasopharyngeal Cancer, Neuroblastoma, Non-Hodgkin's Lymphoma During Pregnancy, Nonmelanoma Skin Cancer, Non-Small Cell Lung Cancer, Occult Primary Metastatic Squamous Neck Cancer, Oropharyngeal Cancer, Osteo-/Malignant Fibrous Sarcoma, Osteosarcoma/Malignant Fibrous Histiocytoma, Osteosarcoma/Malignant Fibrous Histiocytoma of Bone, Ovarian Epithelial Cancer, Ovarian Germ Cell Tumor, Ovarian Low Malignant Potential Tumor, Pancreatic Cancer, Paraproteinemias, Purpura, Parathyroid Cancer, Pheochromocytoma, Pituitary Tumor, Plasma Cell Neoplasm/Multiple Myeloma, Primary Central Nervous System Lymphoma, Primary Liver Cancer, Prostate Cancer, Rectal Cancer, Renal Cell Cancer, Renal Pelvis and Ureter Cancer, Retinoblastoma, Rhabdomyosarcoma, Salivary Gland Cancer, Sarcoidosis Sarcomas, Sezary Syndrome, Skin Cancer, Small Cell Lung Cancer, Small Intestine Cancer, Soft Tissue Sarcoma, Squamous Neck Cancer, Stomach Cancer, Supratentorial Primitive Neuroectodermal and Pineal Tumors, T cell Lymphoma, Testicular Cancer, Thymoma, Thyroid Cancer, Transitional Cell Cancer of the Renal Pelvis and Ureter, Transitional Renal Pelvis and Ureter Cancer, Trophoblastic Tumors, Ureter and Renal Pelvis Cell Cancer, Urethral Cancer, Uterine Cancer, Uterine Sarcoma, Vaginal Cancer, Visual Pathway and Hypothalamic Glioma, Vulvar Cancer, Waldenstrom's Macroglobulinemia, Wilms' Tumor, and any other hyperproliferative disease, besides neoplasia, located in an organ system listed above.

Naturally Occurring Amino Acid Substitutions

List of naturally occurring amino acids and some of their biochemical properties.

3- 1- Side-chain Letter Letter Side-chain charge (pH Hydropathy Amino Acid Code Code polarity* 7.4)* index** Alanine Ala A nonpolar neutral 1.8 Arginine Arg R polar positive −4.5 Asparagine Asn N polar neutral −3.5 Aspartic acid Asp D polar negative −3.5 Cysteine Cys C polar neutral 2.5 Glutamic Glu E polar negative −3.5 acid Glutamine Gln Q polar neutral −3.5 Glycine Gly G nonpolar neutral −0.4 Histidine His H polar positive (10%) −3.2 neutral (90%) Isoleucine Ile I nonpolar neutral 4.5 Leucine Leu L nonpolar neutral 3.8 Lysine Lys K polar positive −3.9 Methionine Met M nonpolar neutral 1.9 Phenylalanine Phe F nonpolar neutral 2.8 Proline Pro P nonpolar neutral −1.6 Serine Ser S polar neutral −0.8 Threonine Thr T polar neutral −0.7 Tryptophan Trp W nonpolar neutral −0.9 Tyrosine Tyr Y polar neutral −1.3 Valine Val V nonpolar neutral 4.2 *Hausman & Cooper, (2004), The Cell: A Molecular Approach, Washington, D.C: ASM Press. p. 51 (2004) (ISBN 0-87893-214-3). **Kyte & Doolittle, “A simple method for displaying the hydropathic character of a protein,” Journal of Molecular Biology, 157 (1): 105-132 (May 1982).

Conservative Amino Acid Substitutions

Polypeptides may be made to differ by introduction of conservative or non-conservative amino acid changes. Conservative amino acid substitutions refer to the interchangeability of residues having similar amino acid side chains. “Conservative amino acid substitutions” refer to substitutions of one or more amino acids in a native amino acid sequence (e.g., wild-type or naturally occurring form of PE) with other amino acid(s) having similar side chains (e.g., side chains similar in terms of size, charge, element composition, and/or hydrophobicity/hydrophilicity).

Conserved substitutes for an amino acid within a native amino acid sequence can be selected from other members of the group to which the naturally occurring amino acid belongs. For example, conservative amino acid residue substitution groups include:

-   -   (1) Alanine (A)-Glycine (G)-Serine (S)-Threonine;     -   (2) Aspartic acid (D)-Glutamic acid (E);     -   (3) Asparagine (N)-Glutamine (Q);     -   (4) Arginine (R)-Lysine (K)-Histidine (H),     -   (5) Isoleucine (I)-Leucine (L)-Methionine (M)-Valine (V); and     -   (6) Phenylalanine (F)-Tyrosine (Y)-Tryptophan (W).

Other substitution groups of amino acids can be envisioned. For example, amino acids can be grouped by similar function or chemical structure or composition (e.g., acidic, basic, aliphatic, aromatic, sulfur-containing). For example, an Aliphatic grouping may comprise: Glycine (G), Alanine (A), Valine (V), Leucine (L), Isoleucine (I). Other groups containing amino acids that are considered conservative substitutions for one another include:

-   -   Aromatic: Phenylalanine (F)-Tyrosine (Y)-Tryptophan (W);     -   Sulfur-containing: Methionine (M)-Cysteine (C);     -   Basic: Arginine (R)-Lysine (K)-Histidine (H);     -   Acidic: Aspartic acid (D)-Glutamic acid (E);     -   Non-polar uncharged residues: Cysteine (C)-Methionine         (M)-Proline (P); and     -   Hydrophilic Uncharged Residues: Serine (S)-Threonine         (T)-Asparagine (N)-Glutamine (Q).

Exemplary embodiments of conservative amino acid substitutions include the interchangeability of: valine-leucine, valine-isoleucine-leucine, phenylalanine-tyrosine, lysine-arginine, alanine-valine, aspartic acid-glutamic acid, and asparagine-glutamine.

Examples of Amino Acid Analogs and Non-Standard Amino Acid Residues

Examples of a few of the many possible amino acid analogs routinely known to those of skill in the art include, for example, but without limitation, analogs such as: 4-hydroxyproline which may be substituted for proline, 5-hydroxylysine which may be substituted for lysine; 3-methylhistidine which may be substituted for histidine; homoserine which may be substituted for serine; and ornithine which may be substituted for lysine.

Examples of a few of the many possible non-standard amino acids routinely known to those of skill in the art include, for example, but without limitation, molecules such as: ornithine, citrulline, lanthionine, 2-aminoisobutyric acid, dehydroalanine, γ-aminobutyric acid, β-alanine (3-aminopropanoic acid), selenocysteine and pyrrolysine.

Substitution mutations may be made by any technique for mutagenesis known in the art including, for example, but not limited to, in vitro site-directed mutagenesis (Hutchinson et al, J. Biol. Chem. 255:6551 (1978); Zoller et al, DNA 3:479 (1984); Oliphant et al, Gene 44:177 (1986); Hutchinson et al, Proc. Natl. Acad. Sci. USA 83:710 (1986)), use of TAB® linkers (Pharmacia), restriction endonuclease digestion/fragment deletion and substitution, PCR-mediated/oligonucleotide-directed mutagenesis, et cetera. PCR-based techniques are preferred for site-directed mutagenesis (see Higuchi, 1989, “Using PCR to Engineer DNA”, in PCR Technology: Principles and Applications for DNA Amplification, H. Erlich, ed., Stockton Press, Chapter 6, pp. 61-70).

Embodiments of the Invention

Embodiments of the invention include isolated polypeptides (proteins) comprising or consisting of a modified form of Pseudomonas exotoxin A, or a fragment thereof, wherein said modified form, or fragment thereof, comprises an epitope selected from the group consisting of:

(epitope 1; SEQ ID NO: 5) ISFSTRGTQ; (epitope 2; SEQ ID NO: 6) GTQNWTVER; (epitope 3; SEQ ID NO: 7) IVFGGVRAR; (epitope 4; SEQ ID NO: 8) ARSQDLDAI; (epitope 5; SEQ ID NO: 9) LRVYVPRSS;  and (epitope 6; SEQ ID NO: 10) IPDKEQAIS 

-   -   wherein one or more amino acid residues in any one or more of         these epitopes are substituted with a different amino acid         residue.

Embodiments of the invention include isolated polypeptides (proteins) comprising or consisting of a modified form of Pseudomonas exotoxin A, or a fragment thereof, wherein said modified form, or fragment thereof, comprises an epitope selected from the group consisting of:

(peptide 50 (epitope 1); SEQ ID NO: 60) GDGGDISFSTRGTQN; (peptide 52 (epitope 2); SEQ ID NO: 62) SFSTRGTQNWTVERL; (peptide 53 (epitope 2); SEQ ID NO: 63) TRGTQNWTVERLLQA; (peptide 65 (epitope 3); SEQ ID NO: 75) AQSIVFGGVRARSQD; (peptide 67 (epitope 4); SEQ ID NO: 77) GGVRARSQDLDAIWR; (peptide 68 (epitope 4); SEQ ID NO: 78) RARSQDLDAIWRGFY; (peptide 81 (epitope 5); SEQ ID NO: 91) NGALLRVYVPRSSLP; (peptide 82 (epitope 5); SEQ ID NO: 92) LLRVYVPRSSLPGFY; (peptide 110 (epitope 6); SEQ ID NO: 120) LDPSSIPDKEQAISA; (peptide 111 (epitope 6); SEQ ID NO: 121) SSIPDKEQAISALPD; (overlapping epitopes 1 and 2; SEQ ID NO: 131) ISFSTRGTQNWTVER; (overlapping epitopes 3 and 4; SEQ ID NO: 132) IVFGGVRARSQDLDAI 

-   -   wherein one or more amino acid residues in any one or more of         these epitopes are substituted with a different amino acid         residue.

Embodiments of the invention include isolated polypeptides (proteins) comprising or consisting of a modified form of Pseudomonas exotoxin A, or a fragment thereof, wherein said modified form, or fragment thereof, comprises an epitope selected from the group consisting of:

-   -   a) ISFSTRGTQ (SEQ ID NO:5), wherein amino acid residues at one         or more of positions 1, 6 and 9 are substituted with a different         amino acid residue;     -   b) GTQNWTVER (SEQ ID NO:6), wherein amino acid residues at one         or more of positions 3, 4 and 6 are substituted with a different         amino acid residue;     -   c) IVFGGVRAR (SEQ ID NO:7), wherein amino acid residues at one         or more of positions 1 and 6 are substituted with a different         amino acid residue;     -   d) ARSQDLDAI (SEQ ID NO:8), wherein amino acid residues at one         or more of positions 4 and 7 are substituted with a different         amino acid residue;     -   e) LRVYVPRSS (SEQ ID NO:9), wherein amino acid residues at one         or more of positions 1, 2 and 9 are substituted with a different         amino acid residue;     -   f) IPDKEQAIS (SEQ ID NO:10), wherein amino acid residues at one         or more of positions 1, 4, 6 and 7 are substituted with a         different amino acid residue;     -   g) ISFSTRGTQNWTVER (SEQ ID NO:131), wherein amino acid residues         at one or more of positions 1, 6, 9, 10 and 12 are substituted         with a different amino acid residue; and     -   h) IVFGGVRARSQDLDAI (SEQ ID NO:132), wherein amino acid residues         at one or more of positions 1, 6, 11, and 14 are substituted         with a different amino acid residue.

Embodiments of the invention include isolated polypeptides (proteins) comprising or consisting of a modified form of Pseudomonas exotoxin A, or a fragment thereof, wherein said modified form, or fragment thereof, comprises an epitope selected from the group consisting of:

-   -   a) ISFSTRGTQ (SEQ ID NO:5), wherein amino acid residues at one         or more of positions 1, 6 and 9 are substituted with a         conservative amino acid substitution;     -   b) GTQNWTVER (SEQ ID NO:6), wherein amino acid residues at one         or more of positions 3, 4 and 6 are substituted with a         conservative amino acid substitution;     -   c) IVFGGVRAR (SEQ ID NO:7), wherein amino acid residues at one         or more of positions 1 and 6 are substituted with a conservative         amino acid substitution;     -   d) ARSQDLDAI (SEQ ID NO:8), wherein amino acid residues at one         or more of positions 4 and 7 are substituted with a conservative         amino acid substitution;     -   e) LRVYVPRSS (SEQ ID NO:9), wherein amino acid residues at one         or more of positions 1, 2 and 9 are substituted with a         conservative amino acid substitution;     -   f) IPDKEQAIS (SEQ ID NO:10), wherein amino acid residues at one         or more of positions 1, 4, 6 and 7 are substituted with a         conservative amino acid substitution;     -   g) ISFSTRGTQNWTVER (SEQ ID NO:131), wherein amino acid residues         at one or more of positions 1, 6, 9, 10 and 12 are substituted         with a conservative amino acid substitution; and     -   h) IVFGGVRARSQDLDAI (SEQ ID NO:132), wherein amino acid residues         at one or more of positions 1, 6, 11, and 14 are substituted         with a conservative amino acid substitution.

Embodiments of the invention include isolated polypeptides (proteins) comprising or consisting of a modified form of Pseudomonas exotoxin A, or a fragment thereof, wherein said modified form, or fragment thereof, comprises an epitope selected from the group consisting of:

-   -   a) ISFSTRGTQ (SEQ ID NO:5), wherein amino acid residues at one         or more of positions 1, 6 and 9 are substituted with a         conservative amino acid substitution;     -   b) GTQNWTVER (SEQ ID NO:6), wherein amino acid residues at one         or more of positions 3, 4 and 6 are substituted with a         conservative amino acid substitution;     -   c) IVFGGVRAR (SEQ ID NO:7), wherein amino acid residues at one         or more of positions 1 and 6 are substituted with a conservative         amino acid substitution;     -   d) ARSQDLDAI (SEQ ID NO:8), wherein amino acid residues at one         or more of positions 4 and 7 are substituted with a conservative         amino acid substitution;     -   e) LRVYVPRSS (SEQ ID NO:9), wherein amino acid residues at one         or more of positions 1, 2 and 9 are substituted with a         conservative amino acid substitution;     -   f) IPDKEQAIS (SEQ ID NO:10), wherein amino acid residues at one         or more of positions 1, 4, 6 and 7 are substituted with a         conservative amino acid substitution;     -   g) ISFSTRGTQNWTVER (SEQ ID NO:131), wherein amino acid residues         at one or more of positions 1, 6, 9, 10 and 12 are substituted         with a conservative amino acid substitution; and     -   h) IVFGGVRARSQDLDAI (SEQ ID NO:132), wherein amino acid residues         at one or more of positions 1, 6, 11, and 14 are substituted         with a conservative amino acid substitution,     -   wherein the conservative amino acid substitution at one or more         of said positions in a) through f) is selected from the group         consisting of:     -   1) A is substituted with any one of G, I, L, S, T or V;     -   2) D is substituted with E;     -   3) I is substituted with any one of L, M or V;     -   4) K is substituted with any one of H or R;     -   5) L is substituted with any one of A, G, I, M or V;     -   6) N is substituted with any one of S, T or Q;     -   7) Q is substituted with any one of S, T or N;     -   8) R is substituted with any one of K or H;     -   9) S is substituted with any one of A, G, N, T or Q;     -   10) T is substituted with any one of A, G, N, Q or S; and     -   11) V is substituted with any one of A, G, I, L or M.

Embodiments of the invention also comprise or consist of isolated polypeptides and peptides comprising or consisting of the above-referenced amino acids sequences, except wherein one or more amino acids have been substituted with conservative amino acids substitutions. Embodiments of the invention further comprise or consist of isolated polypeptides (proteins) and peptides comprising or consisting of the above-referenced amino acids sequences, except wherein one or more amino acids have been substituted with amino acids which are naturally occurring, non-naturally occurring, non-standard amino acids, or amino acid analogs.

Embodiments of the invention include isolated polypeptides (proteins) comprising or consisting of a modified form of Pseudomonas exotoxin A, or a fragment thereof, wherein said modified form, or fragment thereof, comprises an epitope selected from the group consisting of:

-   -   a) ISFSTRGTQ (SEQ ID NO:5), wherein amino the acid residue at         position 1 (I) is substituted with A, N, T, Q or H, or wherein         the amino acid residue at position 6 (R) is substituted with Q,         or wherein the amino acid residue at position 9 (Q) is         substituted with N or T, or wherein the amino acid sequence         ISFSTRGTQ (SEQ ID NO:5) comprises two or more of said         substitutions in any combination;     -   b) GTQNWTVER (SEQ ID NO:6), wherein the amino acid residue at         position 3 (Q) is substituted with N or T, wherein amino the         acid residue at position 4 (N) is substituted with K or R, or         wherein the amino acid residue at position 6 (T) is substituted         with K or R, or wherein the amino acid sequence GTQNWTVER (SEQ         ID NO:6) comprises two or more of said substitutions in any         combination;     -   c) IVFGGVRAR (SEQ ID NO:7), wherein amino the acid residue at         position 1 (I) is substituted with A or N, or wherein the amino         acid residue at position 6 (V) is substituted with D, M, or N,         or wherein the amino acid sequence IVFGGVRAR (SEQ ID NO:7)         comprises substitutions at both positions in any combination of         amino acid residues A or N at position 1 (I) and D, M, or N at         position 6 (V);     -   d) ARSQDLDAI (SEQ ID NO:8), wherein amino the acid residue at         position 4 (Q) is substituted with K or R, or wherein the amino         acid residue at position 7 (D) is substituted with K or R, or         wherein the amino acid sequence ARSQDLDAI (SEQ ID NO:8)         comprises substitutions with K or R in any combination at both         positions 4 (Q) and 7 (D);     -   e) LRVYVPRSS (SEQ ID NO:9), wherein amino the acid residue at         position 1 (L) is substituted with A, or wherein the amino acid         residue at position 2 (R) is substituted with D, S or A, or         wherein the amino acid residue at position 9 (S) is substituted         with D, E, N, K, P or T, or wherein the amino acid sequence         LRVYVPRSS (SEQ ID NO:9) comprises two or more of said         substitutions in any combination;     -   f) IPDKEQAIS (SEQ ID NO:10), wherein amino acid residues at one         or more of positions 1, 4, 6 and 7 are substituted with a         different amino acid residue, wherein amino the acid residue at         position 1 (I) is substituted with A, N, T, Q or H, or wherein         the amino acid residue at position 4 (K) is substituted with T,         or wherein the amino acid residue at position 6 (Q) is         substituted with D, or wherein the amino acid residue at         position 7 (A) is substituted with D, or wherein the amino acid         sequence IPDKEQAIS (SEQ ID NO:10) comprises two or more of said         substitutions in any combination;     -   g) ISFSTRGTQNWTVER (SEQ ID NO:131), wherein amino acid residues         at one or more of positions 1, 6, 9, 10 and 12 are substituted         with a different amino acid residues wherein amino the acid         residue at position 1 (I) is substituted with A, N, T, Q or H,         or wherein the amino acid residue at position 6 (R) is         substituted with Q, or wherein the amino acid residue at         position 9 (Q) is substituted with N or T, or wherein amino the         acid residue at position 10 (N) is substituted with K or R, or         wherein the amino acid residue at position 12 (T) is substituted         with K or R, or wherein the amino acid sequence ISFSTRGTQNWTVER         (SEQ ID NO:131) comprises two or more of said substitutions in         any combination; and     -   h) IVFGGVRARSQDLDAI (SEQ ID NO:132), wherein amino the acid         residue at position 1 (I) is substituted with A or N, or wherein         the amino acid residue at position 6 (V) is substituted with D,         M, or N, wherein amino the acid residue at position 11 (Q) is         substituted with K or R, or wherein the amino acid residue at         position 14 (D) is substituted with K or R, or wherein the amino         acid sequence IVFGGVRARSQDLDAI (SEQ ID NO:132) comprises two or         more of said substitutions in any combination.

Embodiments of the invention include an isolated polypeptide comprising a modified form of Pseudomonas exotoxin A, or a fragment thereof, wherein said modified form, or fragment thereof, comprises one or more amino acid substitutions selected from the group consisting of:

-   -   a) I at position 141 changed to any amino acid residue; (epitope         1)     -   b) R at position 146 changed to any amino acid residue; (epitope         1)     -   c) Q at position 149 changed to any amino acid residue; (epitope         1)     -   d) N at position 150 changed to any amino acid residue; (epitope         2)     -   e) T at position 152 changed to any amino acid residue; (epitope         2)     -   f) I at position 184 changed to any amino acid residue; (epitope         3)     -   g) V at position 189 changed to any amino acid residue; (epitope         3)     -   h) Q at position 194 changed to any amino acid residue; (epitope         4)     -   i) D at position 197 changed to any amino acid residue; (epitope         4)     -   j) L at position 233 changed to any amino acid residue; (epitope         5)     -   k) R at position 234 changed to any amino acid residue; (epitope         5)     -   l) S at position 241 changed to any amino acid residue; (epitope         5)     -   m) I at position 321 changed to any amino acid residue; (epitope         6)     -   n) K at position 324 changed to any amino acid residue; (epitope         6)     -   o) Q at position 326 changed to any amino acid residue; (epitope         6)     -   p) A at position 327 changed to any amino acid residue; (epitope         6)     -   q) any combination of one or more of a) through ao),     -   wherein the amino acid numbering corresponds to SEQ ID NO:1.

Embodiments of the invention include an isolated polypeptide comprising a modified form of Pseudomonas exotoxin A, or a fragment thereof, wherein said modified form, or fragment thereof, comprises one or more amino acid substitutions selected from the group consisting of:

-   -   a) I at position 141 changed to A; (epitope 1)     -   b) I at position 141 changed to N; (epitope 1)     -   c) I at position 141 changed to T, (epitope 1)     -   d) I at position 141 changed to Q; (epitope 1)     -   e) I at position 141 changed to H; (epitope 1)     -   f) R at position 146 changed to Q; (epitope 1)     -   g) Q at position 149 changed to N; (epitope 1)     -   h) Q at position 149 changed to T; (epitope 1)     -   i) N at position 150 changed to R; (epitope 2)     -   j) N at position 150 changed to K; (epitope 2)     -   k) T at position 152 changed to R; (epitope 2)     -   l) T at position 152 changed to K; (epitope 2)     -   m) I at position 184 changed to A; (epitope 3)     -   n) I at position 184 changed to N; (epitope 3)     -   o) V at position 189 changed to D; (epitope 3)     -   p) V at position 189 changed to M; (epitope 3)     -   q) V at position 189 changed to N; (epitope 3)     -   r) Q at position 194 changed to R; (epitope 4)     -   s) Q at position 194 changed to K; (epitope 4)     -   t) D at position 197 changed to R; (epitope 4)     -   u) D at position 197 changed to K; (epitope 4)     -   v) L at position 233 changed to A; (epitope 5)     -   w) R at position 234 changed to D; (epitope 5)     -   x) R at position 234 changed to S; (epitope 5)     -   y) R at position 234 changed to A; (epitope 5)     -   z) S at position 241 changed to D, (epitope 5)     -   ab) S at position 241 changed to E; (epitope 5)     -   ac) S at position 241 changed to N; (epitope 5)     -   ad) S at position 241 changed to K; (epitope 5)     -   ae) S at position 241 changed to P; (epitope 5)     -   af) S at position 241 changed to T; (epitope 5)     -   ag) I at position 321 changed to A; (epitope 6)     -   ah) I at position 321 changed to N; (epitope 6)     -   ai) I at position 321 changed to T; (epitope 6)     -   ak) I at position 321 changed to Q; (epitope 6)     -   al) I at position 321 changed to H; (epitope 6)     -   am) K at position 324 changed to T; (epitope 6)     -   an) Q at position 326 changed to D, (epitope 6)     -   ao) A at position 327 changed to D; (epitope 6)     -   ap) any combination of one or more of a) through ao),     -   wherein the amino acid numbering corresponds to SEQ ID NO:1.

Embodiments of the invention comprise isolated polypeptides as described above, including polypeptides comprising amino acid substitutions introduced at each of amino acid positions 141, 146, 149, 150, 152, 184, 189, 194, 197, 233, 234, 241, 321, 324, 326 and 327 (in comparison to the amino acid sequence of SEQ ID NO:1).

Embodiments of the invention include isolated polypeptides (proteins) and peptides comprising, or consisting of, the following amino acid sequences:

(peptide 1; SEQ ID NO: 11) GGGGGSGGGGGSPEG; (peptide 2; SEQ ID NO: 12) GGSGGGGGSPEGGSL; (peptide 3; SEQ ID NO: 13) GGGGGSPEGGSLAAL; (peptide 4; SEQ ID NO: 14) GGSPEGGSLAALTAH; (peptide 5; SEQ ID NO: 15) PEGGSLAALTAHQAC; (peptide 6; SEQ ID NO: 16) GSLAALTAHQACHLP; (peptide 7; SEQ ID NO: 17) AALTAHQACHLPLET; (peptide 8; SEQ ID NO: 18) TAHQACHLPLETFTR; (peptide 9; SEQ ID NO: 19) QACHLPLETFTRQRQ; (peptide 10; SEQ ID NO: 20) HLPLETFTRHRQPRG; (peptide 11; SEQ ID NO: 21) LETFTRHRQPRGWEQ; (peptide 12; SEQ ID NO: 22) FTRHRQPRGWEQLEQ; (peptide 13; SEQ ID NO: 23) HRQPRGWEQLEQCGY; (peptide 14; SEQ ID NO: 24) PRGKEQLEQCGYPVQ; (peptide 15; SEQ ID NO: 25) WEQLEQCGYPVQRLV; (peptide 16; SEQ ID NO: 26) LEQCGYPVQRLVALY; (peptide 17; SEQ ID NO: 27) CGYPVQRLVALYLAA; (peptide 18; SEQ ID NO: 28) PVQRLVALYLAARLS; (peptide 19; SEQ ID NO: 29) RLVALYLAARLSWNQ; (peptide 20; SEQ ID NO: 30) ALYLAARLSWNQVDQ; (peptide 21; SEQ ID NO: 31) LAARLSWNQVDQVIR; (peptide 22; SEQ ID NO: 32) RLSKNQVDQVIRNAL; (peptide 23; SEQ ID NO: 33) WNQVDQVIRNALASP; (peptide 24; SEQ ID NO: 34) VDQVIRNALASPGSG; (peptide 25; SEQ ID NO: 35) VIRNALASPGSGGDL; (peptide 26; SEQ ID NO: 36) NALASPGSGGDLGEA; (peptide 27; SEQ ID NO: 37) ASPGSGGDLGEAIRE; (peptide 28; SEQ ID NO: 38) GSGGDLGEAIREQPE; (peptide 29; SEQ ID NO: 39) GDLGEAIREQPEQAR; (peptide 30; SEQ ID NO: 40) GEAIREQPEQARLAL; (peptide 31; SEQ ID NO: 41) IREQPEQARLALTLA; (peptide 32; SEQ ID NO: 42) QPEQARLALTLAAAE; (peptide 33; SEQ ID NO: 43) QARLALTLAAAESER; (peptide 34; SEQ ID NO: 44) LALTLAAAESERFVR; (peptide 35; SEQ ID NO: 45) TLAAAESERFVRQGT; (peptide 36; SEQ ID NO: 46) AAESERFVRQGTGND; (peptide 37; SEQ ID NO: 47) SERFVRQGTGNDEAG; (peptide 38; SEQ ID NO: 48) FVRQGTGNDEAGAAS; (peptide 39; SEQ ID NO: 49) QGTGNDEAGAASGPA; (peptide 40; SEQ ID NO: 50) GNDEAGAASGPADSG; (peptide 41; SEQ ID NO: 51) EAGAASGPADSGDAL; (peptide 42; SEQ ID NO: 52) AASGPADSGDALLER; (peptide 43; SEQ ID NO. 53) GPADSGDALLERNYP; (peptide 44; SEQ ID NO: 54) DSGDALLERNYPTGA; (peptide 45; SEQ ID NO: 55) DALLERNYPTGAEFL; (peptide 46; SEQ ID NO: 56) LERNYPTGAEFLGDG; (peptide 47; SEQ ID NO: 57) NYPTGAEFLGDGGDI; (peptide 48; SEQ ID NO: 58) TGAEFLGDGGDISFS; (peptide 40; SEQ ID NO: 59) EFLGDGGDISFSTRG; (peptide 51; SEQ ID NO: 61) GDISFSTRGTQNWTV; (peptide 54; SEQ ID NO: 64) TQNHTVERLLQAHRQ; (peptide 55; SEQ ID NO: 65) WTVERLLQAHRQLEE; (peptide 56; SEQ ID NO: 66) ERLLQAHRQLEERGY; (peptide 57; SEQ ID NO: 67) LQAHRQLEERGYVFV; (peptide 58; SEQ ID NO: 68) HRQLEERGYVFVGYH; (peptide 50; SEQ ID NO: 69) LEERGYVFVGYHGTF; (peptide 60; SEQ ID NO: 70) RGYVFVGYHGTFLEA; (peptide 61; SEQ ID NO: 71) VFVGYHGTFLEAAQS; (peptide 62; SEQ ID NO: 72) GYHGTFLEAAQSIVF; (peptide 63; SEQ ID NO: 73) GTFLEAAQSIVFGGV; (peptide 64; SEQ ID NO: 74) LEAAQSIVFGGVRAR; (peptide 66; SEQ ID NO: 76) IVFGGVRARSQDLDA; (peptide 69; SEQ ID NO: 79) SQDLDAIKRGFYIAG; (peptide 70; SEQ ID NO: 80) LDAIWRGFYIAGDPA; (peptide 71; SEQ ID NO: 81) IWRGFYIAGDPALAY; (peptide 72; SEQ ID NO: 82) GFYIAGDPALAYGYA; (peptide 73; SEQ ID NO: 83) IAGDPALAYGYAQDQ; (peptide 74; SEQ ID NO: 84) DPALAYGYAQDQEPD; (peptide 75; SEQ ID NO: 85) LAYGYAQDQEPDARG; (peptide 76; SEQ ID NO: 86) GYAQDQEPDARGRIR; (peptide 77; SEQ ID NO: 87) QDQEPDARGRIRNGA; (peptide 78; SEQ ID NO: 88) EPDARGRIRNGALLR; (peptide 79; SEQ ID NO: 89) ARGRIRNGALLRVYV; (peptide 80; SEQ ID NO: 90) RIRNGALLRVYVPRS; (peptide 83; SEQ ID NO: 93) VYVPRSSLPGFYRTG; (peptide 84; SEQ ID NO: 94) PRSSLPGFYRTGLTL; (peptide 85; SEQ ID NO: 95) SLPGFYRTGLTLAAP; (peptide 86; SEQ ID NO: 96) GFYRTGLTLAAPEAA; (peptide 87; SEQ ID NO: 97) RTGLTLAAFEAAGEV; (peptide 88; SEQ ID NO: 98) LTLAAPEAAGEVERL; (peptide 89; SEQ ID NO: 99) AAPEAAGEVERLIGH; (peptide 90; SEQ ID NO: 100) EAAGEVERLIGHPLP; (peptide 91; SEQ ID NO: 101) GEVERLIGHPLPLRL; (peptide 92; SEQ ID NO: 102) ERLIGHPLPLRLDAI; (peptide 93; SEQ ID NO: 103) IGHPLPLRLDAITGP; (peptide 94; SEQ ID NO: 104) PLPLRLDAITGPEEE; (peptide 95; SEQ ID NO: 105) LRLDAITGPEEEGGR; (peptide 96; SEQ ID NO: 106) DAITGPEEEGGRLET; (peptide 97; SEQ ID NO: 107) TGPEEEGGRLETILG; (peptide 98; SEQ ID NO: 108) EEEGGRLETILGWPL; (peptide 99; SEQ ID NO: 109) GGRLETILGWPLAER; (peptide 100; SEQ ID NO: 110) LETILGWPLAERTVV; (peptide 101; SEQ ID NO: 111) ILGWPLAERTVVIPS; (peptide 102; SEQ ID NO: 112) WPLAERTVVIPSAIP; (peptide 103; SEQ ID NO; 113) AERTVVIPSAIPTDP; (peptide 104; SEQ ID NO: 114) TVVIPSAIPTDPRNV  (peptide 105; SEQ ID NO: 115) IPSAIPTDPRNVGGD; (peptide 106; SEQ ID NO: 116) AIPTDPRNVGGDLDP; (peptide 107; SEQ ID NO: 117) TDPRNVGGDLDPSSI; (peptide 108; SEQ ID NO: 118) RNVGGDLDPSSIPDK; (peptide 100; SEQ ID NO: 119) GGDLDPSSIPDKEQA; (peptide 112; SEQ ID NO: 122) PDKEOAISALPDYAS; (peptide 113; SEQ ID NO: 123) EQAISALPDYASQPG; (peptide 114; SEQ ID NO: 124) ISALPDYASQPGKPP; (peptide 115; SEQ ID NO: 125) LPDYASQPGKPPRED; (peptide 116; SEQ ID NO: 126) YASQPGKPPREDLN; (peptide 117; SEQ ID NO: 127) ITGPEEEGGRLDTIL; (peptide 118; SEQ ID NO: 128) PEEEGGRLDTILGKP; (peptide 119; SEQ ID NO: 129) EGGRLDTILGWPLAE; and (peptide 120; SEQ ID NO: 130) RLDTILGWPLAERTV.

Embodiments of the invention also comprise or consist of isolated polypeptides (proteins) and peptides comprising or consisting of the above-referenced amino acids sequences, except wherein one or more amino acids have been substituted with conservative amino acids substitutions. Embodiments of the invention also comprise or consist of isolated polypeptides (proteins) and peptides comprising or consisting of the above-referenced amino acids sequences, except wherein one or more amino acids have been substituted with amino acids which are naturally occurring, non-naturally occurring, non-standard amino acids, or amino acid analogs.

Embodiments of the invention include polypeptides comprising a PE-A Domain III (i.e., a cytotoxic domain; see e.g., FIG. 1). Examples of sequences comprising a cytotoxic portion of PE can be found in SEQ ID NO:1 and SEQ ID NO:4 spanning amino acid residues Phe-134 to Lys-347. Examples of sequences comprising a cytotoxic portion of PE can also be found in SEQ ID NO:133 and SEQ ID NO:134 spanning amino acid residues Phe-400 to Lys-613.

Embodiments of the invention include polypeptides comprising a PE-A Domain III (i.e., a cytotoxic domain) and one or more PE-A domains selected from the group consisting of:

-   -   (a) Domain II (i.e., a cytosolic translocation domain, e.g.,         amino acids corresponding to Gly-3 to Ser-114 in SEQ ID NO:1 or         amino acids corresponding to Gly-3 to Asn-114 in SEQ ID NO:4,         see e.g., FIG. 1);     -   (b) Carboxy-terminal portion of Domain IB (e.g., amino acids         corresponding to Gly-115 to Glu-133 in SEQ ID NO:1 or SEQ ID         NO:4; and amino acids corresponding to Gly-381 to Glu-399 in SEQ         ID NO:133 or SEQ ID NO:134; see e.g., FIG. 1);     -   (c) Amino-terminal portion of Domain IB (e.g., amino acids         corresponding to Ala-365 to Ala-380 in SEQ ID NO:133 or SEQ ID         NO:134; see e.g., FIG. 1);     -   (d) Domain IB (i.e., amino acid sequences intervening between         Domains II and III; e.g., amino acids corresponding to Ala-365         to Glu-399 in SEQ ID NO:133 or SEQ ID NO:134; see e.g., FIG. 1);     -   (e) a carboxy-terminal tail selected from the group consisting         of:

(i)  (SEQ ID NO: 135) Arg-Glu-Asp-Leu-Lys; (ii)  (SEQ ID NO: 136) Arg-Glu-Asp-Leu;  and (iii)  (SEQ ID NO: 137) Lys-Asp-Glu-Leu,

-   -   wherein one or more of said domains has been modified with amino         acid substitutions, as described herein, to reduce or eliminate         immunogenicity.

Embodiments of the invention further comprise PE variants. For example, such variants include, without limitation, PE polypeptide examples as shown in SEQ ID Nos: 143 to 163 and SEQ ID No: 175.

Embodiments of the invention comprise any one or more of the PE-A domains indicated in the preceding paragraphs, wherein said one or more domains are chemically linked, covalently coupled, or fused (i.e., as in-frame fusion proteins) with a heterologous polypeptide (for example, such as ligand or antigen-binding polypeptide).

Embodiments of the invention include polypeptides comprising PE wherein one or more amino acids are substituted with any combination of one or more conservative amino acid substitutions, non-conservative amino acid substitutions, non-naturally occurring amino acid substitutions, non-standard amino acids, and/or substitutions with amino acid analogs and further wherein said polypeptides are non-immunogenic or exhibit reduced immunogenicity as determined and assayed by comparison to immunogenicity of corresponding non-amino acid substituted forms of PE; as measured using in vitro or in vivo assays. In particular embodiments, amino acid substituted forms of PE are at least 25%, at least about 25%, at least 50%, at least about 50%, at least 75%, or at least about 75% less immunogenic compared to corresponding non-amino acid substituted forms of PE. In particular embodiments, amino acid substituted forms of PE are at least 2-fold, at least about 2-fold, at least 3-fold, at least about 3-fold, at least 4-fold, at least about 4-fold, at least 5-fold, at least about 5-fold, at least 10-fold, at least about 10-fold, at least 50-fold, at least about 50-fold, at least 100-fold, at least about 100-fold, at least 500-fold, at least about 500-fold, at least 1000-fold, or at least about 1000-fold less immunogenic compared to corresponding non-amino acid substituted forms of PE. In one embodiment, amino acid substituted forms of PE are non-immunogenic or exhibit undetectable immunogenicity compared to corresponding non-amino acid substituted forms of PE.

The immunogenicity of substituted peptides may be measured via assays routinely known and used by those of skill in the art. For example, immunogenicity may be assayed by methods including, but not limited to, the proliferation assays described in Example 1 herein.

Additionally, methods for predicting, and assays for assessing, immunogenicity include those methods and assays such as described or referenced in:

-   Baker M P and Jones T D. Identification and removal of     immunogenicity in therapeutic proteins. Curr. Opin. Drug. Disc. Dev.     2007 10(2): 219-227. -   Bryson C J, Jones T D, Baker M P. Prediction of immunogenicity of     therapeutic proteins: validity of computational tools. BioDrugs.     2010; 24(1):1-8. -   Chester, K, Baker, M P and Mayer A. Overcoming the immunologic     response to foreign enzymes in cancer therapy. Expert Rev. Clin.     Immunol 2006 1(4): 549-559. -   Hochuli E. Interferon immunogenicity: technical evaluation of     interferon-alpha 2a. J Interferon Cytokine Res. 1997 17 Suppl     1:S15-21. -   Jaber A and Baker M P. Assessment of the immunogenicity of different     interferon beta-1a formulations using ex vivo T cell assays. J Pharm     Biomed Anal 2007 43(4):1256-61. -   Perry L C, Jones T D and Baker M P. New approaches to prediction of     immune responses to therapeutic proteins during preclinical     development. Drugs R D. 2008 9(6):385-96. -   Schellekens, H., Ryff, J. C., and Van Der Meide, P. H. Assays for     antibodies to human interferon-alpha: the need for     standardization. J. Interferon Cytokine Res. 1997 17(Suppl. 1),     S5-S8.

Embodiments of the invention include polypeptides comprising PE wherein one or more amino acids are substituted with any combination of one or more conservative amino acid substitutions, non-conservative amino acid substitutions, non-naturally occurring amino acid substitutions, non-standard amino acids, and/or substitutions with amino acid analogs and further wherein said polypeptides retain biological activity as determined and assayed by comparison to biological activities of corresponding non-amino acid substituted forms of PE; such as, but not limited to, cell killing activity, cell cytotoxicity, inactivation of the translation elongation factor EF-2, ADP-ribosylation of EF-2, and inhibition of protein synthesis as measured using in vitro or in vivo assays. In particular embodiments, amino acid substituted forms of PE exhibit 100% or about 100% of biological activity compared to corresponding non-amino acid substituted forms of PE. In particular embodiments, amino acid substituted forms of PE exhibit at least 95%, or at least about 95% of biological activity compared to corresponding non-amino acid substituted forms of PE. In particular embodiments, amino acid substituted forms of PE exhibit at least 90%, at least about 90%, at least 85%, at least about 85%, at least 80%, at least about 80%, at least 75%, at least about 75%, at least 70%, at least about 70%, at least 60%, at least about 60%, at least 50%, or at least about 50% of biological activity compared to corresponding non-amino acid substituted forms of PE.

Embodiments of the invention further comprise fusion proteins, conjugates, covalently-linked, and non-covalently linked amino acid substituted forms of PE, or fragments thereof, as described herein. Amino acid substituted forms of PE may be fused, conjugated or otherwise linked with any artificial, recombinant, or naturally occurring molecule or polypeptide to modify PE activity and/or PE localization/targeting, such as by conferring to PE, via said fusion or conjugation, the tissue targeting, cell targeting, or sub-cellular localization properties of the molecule to which PE is fused, conjugated or otherwise linked. For example, but without limitation, amino acid substituted forms, or fragments thereof of PE may be fused, conjugated, or otherwise linked with any type of antibody or antigen-binding fragments thereof, cell-surface receptor, secreted or cell-surface ligand, or fragments thereof.

In one embodiment, amino acid substituted forms of PE, including amino acid substituted forms of PE fused, conjugated or otherwise linked to another molecule or polypeptide are useful in the treatment of cancer; including, but not limited to, types of cancer described herein. In one embodiment, amino acid substituted forms of PE as described herein are useful for the preparation of a medicament for the treatment of cancer, including, but not limited to, types of cancer described herein.

In one embodiment, amino acid substituted forms of PE, or fragments thereof, may be fused, conjugated, or otherwise linked, without limitation, antigen-binding moieties such as antibodies, or fragments thereof, which specifically or preferentially bind to disease associated antigens. Such molecules include, for example, but without limitation, antibodies indicated in Table 1.

TABLE 1 Examples of Antibodies and Therapeutic Uses TRADE Putative Antigen Example(s) of Therapeutic NAME NAME Targets Use 3F8 GD2 neuroblastoma ABAGOVOMAB CA-125 ovarian cancer (imitation) ABCIXIMAB REOPRO CD41 (integrin platelet aggregation alpha-IIb) inhibitor ADALIMUMAB HUMIRA TNF-α rheumatoid arthritis etc. ADECATUMUMAB EpCAM prostate and breast cancer AFELIMOMAB TNF-α sepsis AFUTUZUMAB CD20 lymphoma ALACIZUMAB VEGFR2 cancer PEGOL ALD518 IL-6 rheumatoid arthritis ALEMTUZUMAB CAMPATH, CD52 CLL, CTCL MABCAMPATH ALTUMOMAB HYBRI- CEA colorectal cancer PENTETATE CEAKER (diagnosis) ANATUMOMAB TAG-72 non-small cell lung MAFENATOX carcinoma ANRUKINZUMAB IL-13 antigen-induced pulmonary inflammation, asthma ATOLIZUMAB HLA-DR hematological cancers ARCITUMOMAB CEA-SCAN CEA gastrointestinal cancers (diagnosis) ASELIZUMAB L-selectin severely injured patients (CD62L) ATLIZUMAB ACTEMRA, IL-6 receptor rheumatoid arthritis ROACTEMRA ATOROLIMUMAB Rhesus factor hemolytic disease of the newborn BAPINEUZUMAB beta amyloid Alzheimer's disease BASILIXIMAB SIMULECT CD25 (α chain of prevention of organ IL-2 receptor) transplant rejections BAVITUXIMAB phosphatidylserine cancer, viral infections BECTUMOMAB LYMPHOSCAN CD22 non-Hodgkin's lymphoma (detection) BELIMUMAB BENLYSTA, BAFF non-Hodgkin lymphoma LYMPHOSTAT-B etc. BENRALIZUMAB CD125 asthma BERTILIMUMAB CCL11 (eotaxin-1) severe allergic disorders BESILESOMAB SCINTLMUN CEA-related inflammatory lesions and antigen metastases (detection) BEVACIZUMAB AVASTIN VEGF-A metastatic cancer BICIROMAB FIBRISCENT fibrin II, beta chain thromboembolism (diagnosis) BIVATUZUMAB CD44 v6 squamous cell carcinoma MERTANSINE BLINATUMOMAB CD19 cancer BRENTUXIMAB CD30 (TNFRSF8) hematologic cancers VEDOTIN BRIAKINUMAB IL-I2, IL-23 psoriasis, rheumatoid arthritis, inflammatory bowel diseases, multiple sclerosis CANAKINUMAB ILARIS IL-1 rheumatoid arthritis CANTUZUMAB mucin CanAg colorectal cancer etc. MERTANSINE CAPROMAB PROSTASCINT prostatic prostate cancer (detection) PENDETIDE carcinoma cells CATUMAXOMAB REMOVAB EpCAM, CD3 ovarian cancer, malignant ascites, gastric cancer CC49 TAG-72 tumor detection CEDELIZUMAB CD4 prevention of organ transplant rejections, treatment of autoimmune diseases CERTOLIZUMAB CIMZIA TNF-α Crohn's disease PEGOL CETUXIMAB ERBITUX EGFR metastatic colorectal cancer and head and neck cancer CITATUZUMAB EpCAM ovarian cancer and other BOGATOX solid tumors CIXUTUMUMAB IGF-1 receptor solid tumors CLENOLIXIMAB CD4 rheumatoid arthritis CLIVATUZUMAB MUC1 pancreatic cancer TETRAXETAN CONATUMUMAB TRAIL-R2 cancer CR6261 Influenza A infectious disease/influenza A hemagglutinin DACETUZUMAB CD40 hematologic cancers DACLIZUMAB ZENAPAX CD25 (α chain of prevention of organ IL-2 receptor) transplant rejections DARATUMUMAB CD38 (cyclic ADP myleoma, CD38-positive ribose hydrolase) multiple myeloma DENOSUMAB PROLIA RANKL osteoporosis, bone metastases etc. DETUMOMAB B-lymphoma cell lymphoma DORLIMOMAB auto immune auto immune disorders ARITOX associated antigen DORLIXIZUMAB CD3 type 1 diabetes, autoimmune diseases ECROMEXIMAB GD3 ganglioside malignant melanoma ECULIZUMAB SOLIRIS C5 paroxysmal nocturnal hemoglobinuria EDOBACOMAB Endotoxin sepsis caused by Gram- negative bacteria EDRECOLOMAB PANOREX EpCAM colorectal carcinoma EFALIZUMAB RAPTIVA LFA-1 (CD11a) psoriasis (blocks T-cell migration) EFUNGUMAB MYCOGRAB Hsp90 invasive Candida infection ELOTUZUMAB SLAMF7 multiple myeloma ELSILIMOMAB IL-6 Lymphoma, myeloma ENLIMOMAB/ ICAM-1 (CD54) stroke ENLIMOMAB PEGOL EPITUMOMAB Episialin cancer CITUXETAN EPRATUZUMAB CD22 cancer, SLE ERLIZUMAB ITGB2 (CD18) heart attack, stroke, traumatic shock ERTUMAXOMAB REXOMUN HER2/neu, CD3 breast cancer etc. ETARACIZUMAB ABEGRIN integrin αvβ3 melanoma, prostate cancer, ovarian cancer etc. EXBIVIRUMAB hepatitis B surface hepatitis B antigen FANOLESOMAB NEUTROSPE C CD15 appendicitis (diagnosis) FARALIMOMAB interferon receptor autoimmune disorders FARLETUZUMAB folate receptor 1 ovarian cancer FELVIZUMAB respiratory respiratory syncytial virus syncytial virus infection FEZAKINUMAB IL-22 rheumatoid arthritis, psoriasis FIGITUMUMAB IGF-1 receptor adrenocortical carcinoma, non-small cell lung carcinoma etc. FONTOLIZUMAB HUZAF IFN-γ Crohn's disease etc. FORAVIRUMAB rabies virus rabies (prophylaxis) glycoprotein FRESOLIMUMAB TGF-β idiopathic pulmonary fibrosis, focal segmental glomerulosclerosis, cancer GALIXIMAB CD80 B-cell lymphoma GANTENERUMAB beta amyloid Alzheimer's disease GAVILIMOMAB CD147 (basigin) graft versus host disease GEMTUZUMAB MYLOTARG CD33 acute myelogenous OZOGAMICIN leukemia GIRENTUXIMAB RENCAREX carbonic clear cell renal cell anhydrase 9 (CA- carcinoma IX) GLEMBATUMUMAB GPNMB melanoma, breast cancer VEDOTIN GOLIMUMAB SIMPONI TNF-α rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis GOMILIXIMAB CD23 (IgE allergic asthma receptor) IBALIZUMAB CD4 HIV infection IBRITUMOMAB ZEVALIN CD20 non-Hodgkin's lymphoma TIUXETAN IGOVOMAB INDIMACIS- CA-125 ovarian cancer (diagnosis) 125 IMCIROMAB MYOSCINT cardiac myosin cardiac imaging INFLIXIMAB REMICADE TNF-α rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, psoriasis, Crohn's disease, ulcerative colitis INTETUMUMAB CD51 solid tumors (prostate cancer, melanoma) INOLIMOMAB CD25 (α chain of graft versus host disease IL-2 receptor) INOTUZUMAB CD22 cancer OZOGAMICIN IPILIMUMAB YERVOY CD152 melanoma IRATUMUMAB CD30 (TNTRSF8) Hodgkin's lymphoma KELIXLMAB CD4 chronic asthma LABETUZUMAB CEA-CIDE CEA colorectal cancer LEBRIKIZUMAB IL-13 asthma LEMALESOMAB NCA-90 diagnostic agent (granulocyte antigen) LERDELIMUMAB TGF beta 2 reduction of scarring after glaucoma surgery LEXATUMUMAB TRAIL-R2 cancer LIBIVIRUMAB hepatitis B surface hepatitis B antigen LINTUZUMAB CD33 cancer LORVOTUZUMAB CD56 cancer MERTANSINE LUCATUMUMAB CD40 multiple myeloma, non- Hodgkin's lymphoma, Hodgkin's lymphoma LUMILIXIMAB CD23 (IgE chronic lymphocytic receptor) leukemia MAPATUMUMAB TRAIL-R1 cancer MASLIMOMAB T-cell receptor autoimmune disorders MATUZUMAB EGFR colorectal, lung and stomach cancer MEPOLIZUMAB BOSATRIA IL-5 asthma and white blood cell diseases METELIMUMAB TGF beta 1 systemic scleroderma MILATUZUMAB CD74 multiple myeloma and other hematological malignancies MINRETUMOMAB TAG-72 cancer MITUMOMAB GD3 ganglioside small cell lung carcinoma MOROLIMUMAB Rhesus factor disease antigen MOTAVIZUMAB NUMAX respiratory respiratory syncytial virus syncytial virus (prevention) MUROMONAB- ORTHOCLONE CD3 prevention of organ CD3 OKT3 transplant rejections NACOLOMAB C242 antigen colorectal cancer TAFENATOX NAPTUMOMAB 5T4 non-small cell lung ESTAFENATOX carcinoma, renal cell carcinoma NATALIZUMAB TYSABRI integrin α4 multiple sclerosis, Crohn's disease NEBACUMAB Endotoxin sepsis NECITUMUMAB EGFR non-small cell lung carcinoma NERELIMOMAB TNF-α auto immune disorders NIMOTUZUMAB THERACIM, EGFR squamous cell carcinoma, THERALOC head and neck cancer, nasopharyngeal cancer, glioma NOFETUMOMAB VERLUMA cancer-associated cancer (diagnosis) MERPENTAN antigen OCRELIZUMAB CD20 rheumatoid arthritis, lupus erythematosus etc. ODULIMOMAB LFA-1 (CD11a) prevention of organ transplant rejections, immunological diseases OFATUMUMAB ARZERRA CD20 chronic lymphocytic leukemia OLARATUMAB PDGF-R α cancer OMALIZUMAB XOLAIR IgE Fc region allergic asthma OPORTUZUMAB EpCAM cancer MONATOX OREGOVOMAB OVAREX CA-125 ovarian cancer OTELIXIZUMAB CD3 diabetes mellitus type 1 PAGIBAXIMAB lipoteichoic acid sepsis (Staphylococcus) PALIVIZUMAB SYNAGIS, respiratory respiratory syncytial virus ABBOSYNAGIS syncytial virus (prevention) PANITUMUMAB VECTIBIX EGFR colorectal cancer PANOBACUMAB Pseudomonas Pseudomonas aeruginosa aeruginosa infection PASCOLIZUMAB IL-4 asthma REMTUMOMAB THERAGYN MUC1 cancer PERTUZUMAB OMNITARG HER2/neu cancer PEXELIZUMAB C5 reduction of side effects of cardiac surgery PINTUMOMAB adenocarcinoma adenocarcinoa antigen PRILIXIMAB CD4 Crohn's disease, multiple sclerosis PRITUMUMAB vimentin brain cancer PRO 140 CCR5 HIV infection RAFIVIRUMAB rabies virus rabies (prophylaxis) glycoprotein RAMUCIRUMAB VEGFR2 solid tumors RANIBIZUMAB LUCENTIS VEGF-A macular degeneration (wet form) RAXIBACUMAB anthrax toxin, anthrax (prophylaxis and protective antigen treatment) REGAVIRUMAB cytomegalovirus cytomegalovirus infection glycoprotein B RESLIZUMAB IL-5 inflammations of the airways, skin and gastrointestinal tract RILOTUMUMAB HGF solid tumors RITUXIMAB MABTHERA, CD20 lymphomas, leukemias, RITUXAN some autoimmune disorders ROBATUMUMAB IGF-1 receptor cancer RONTALIZUMAB IFN-α systemic lupus erythematosus ROVELIZUMAB LEUKARREST CD11, CD18 haemorrhagic shock RUPLIZUMAB ANTOVA CD154 (CD40L) rheumatic diseases SATUMOMAB TAG-72 cancer PENDETIDE SEVIRUMAB cytomegalovirus cytomegalovirus infection SIBROTUZUMAB FAP cancer SIFALIMUMAB IFN-α SLE, dermatomyositis, polymyositis SILTUXIMAB IL-6 cancer SIPLIZUMAB CD2 psoriasis, graft-versus-host disease (prevention) SOLANEZUMAB beta amyloid Alzheimer's disease SONEPCIZUMAB sphingosine-1- choroidal and retinal phosphate neovascularization SONTUZUMAB episialin disease antigen STAMULUMAB myostatin muscular dystrophy SULESOMA LEUKOSCAN NCA-90 osteomyelitis (imaging) (granulocyte antigen) TACATUZUMAB AFP-CIDE alpha-fetoprotein cancer TETRAXETAN TADOCIZUMAB integrin αIIbβ3 percutaneous coronary intervention TALIZUMAB IgE allergic reaction TANEZUMAB NGF pain TAPLITUMOMAB CD19 cancer PAPTOX TEFIBAZUMAB AUREXIS clumping factor A Staphylococcus aureus infection TELIMOMAB autoimmune autoimmune disorders ARITOX antigen TENATUMOMAB tenascin C cancer TENELIXIMAB CD40 autoimmune disorders TEPLIZUMAB CD3 diabetes mellitus type 1 TGN1412 CD2 chronic lymphocytic leukemia, rheumatoid arthritis TICILIMUMAB CTLA-4 cancer TIGATUZUMAB TRAIL-R2 cancer TNX-650 IL-13 Hodgkin's lymphoma TOCILIZUMAB ACTEMRA, IL-6 receptor rheumatoid arthritis ROACTEMRA TORALIZUMAB CD154 (CD40L) rheumatoid arthritis, lupus nephritis TOSITUMOMAB BEXXAR CD20 follicular lymphoma TRASTUZUMAB HERCEPTIN HER2/neu breast cancer TREMELIMUMAB CTLA-4 cancer TUCOTUZUMAB EpCAM cancer CELMOLEUKIN TUVIRUMAB hepatitis B virus chronic hepatitis B URTOXAZUMAB Escherichia coli diarrhoea caused by E. coli USTEKINUMAB STELARA IL-12, IL-23 multiple sclerosis, psoriasis, psoriatic arthritis VAPALIXIMAB AOC3 (VAP-1) autoimmune disorders VEDOLIZUMAB integtin α4β7 Crohn's disease, ulcerative colitis VELTUZUMAB CD20 non-Hodgkin's lymphoma VEPALIMOMAB AOC3 (VAP-1) inflammation VISILIZUMAB NUVION CD3 Crohn's disease, ulcerative colitis VOLOCIXIMAB integrin α5β1 solid tumors VOTUMUMAB HUMASPECT tumor antigen colorectal tumors CTAA16.88 ZALUTUMUMAB HUMAX- EGFR squamous cell carcinoma of EGFR the head and neck ZANOLIMUMAB HUMAX-CD4 CD4 rheumatoid arthritis, psoriasis, T-cell lymphoma ZIRALIMUMAB CD147 (basigin) autoimmune disorders ZOLIMOMAB CD5 systemic lupus ARITOX erythematosus, graft-versus- host disease

In certain embodiments, amino acid substituted forms of PE, or fragments thereof, may be fused, conjugated, or otherwise linked, without limitation, to naturally occurring normal or disease related molecules such as secreted, extracellular, intracellular, transmembrane, or cell-surface-bound molecules or fragments thereof (or non-naturally occurring variants and fragments thereof), such as without limitation: ligands, receptors, receptor extracellular domains, cytokines, growth factors, cell signaling proteins, extracellular and intracellular enzymes, structural proteins, cell adhesion proteins and molecules, cluster of differentiation (CD) molecules, mitogens, cell division regulating molecules, cancer/tumor markers and antigens, et cetera. In certain embodiments, molecules which are normally transmembrane and cell-surface bound polypeptides may be fused or conjugated to amino acid substituted forms of PE as polypeptide fragments lacking at least their transmembrane domains or polypeptide regions responsible for cell-surface binding.

In certain embodiments, molecules may be fused or conjugated to amino acid substituted forms of PE wherein such molecules possess or retain the ability (even as fusion proteins or protein conjugates) to form multimeric complexes (such as hetero- and homopolymers including, but not limited to, dimers, trimers, tetramers, pentamers, hexamers, et cetera.)

In certain embodiments, amino acid substituted forms of PE, or fragments thereof, may be generated as in-frame polypeptide fusion proteins with molecules (such as, but not limited to, those referenced above) wherein the PE moiety is either an amino-terminal portion or a carboxyl-terminal portion of the fusion protein. Determination of which of these two configurations provides the desired results and/or biological activities may be determined by routine experimentation practiced by those skilled in the art.

In certain embodiments, amino acid substituted forms of PE, or fragments thereof, may be generated as fusion proteins wherein heterologous amino acid sequences (such as cell targeting sequences) are inserted within the amino acid substituted form of PE (i.e., heterologous amino acids are flanked at the amino terminus and at the carboxy terminus by PE amino acid sequences). An example of a non-amino acid substituted form of PE in such a configuration is demonstrated in U.S. Pat. No. 8,854,044 wherein a TGF-α polypeptide is incorporated at amino acid residues 607 to 604 within a “PE37” polypeptide sequence. See e.g., U.S. Pat. No. 8,854,044, FIG. 1.

Some examples of molecules which may be fused, conjugated, or otherwise linked to amino acid substituted forms of PE, include for example, but without limitation, those such as indicated in Table 2.

TABLE 2 Examples of Potential Compounds and Indications to which Amino Acid Substituted Forms of PE May Be Fused or Conjugated for Therapeutic Use Note: The potential indications and nucleic acid and amino acid sequences shown in Table 2 (as well as accession numbers listed) are presented for purposes of providing a few illustrative examples only. Thus, embodiments of the invention may or may not comprise these  indications and sequences. Accordingly, it is envisioned that embodiments of the invention comprise other indication uses as well as other molecules and sequence variants (e.g., naturally occurring variants (such as allelic or polymorphic variants) and non-naturally occurring variants (such as genetically engineered or mutated variants)) of these sequences wherein one or multiple amino acids are changed and/or wherein only a fragment or fragments of such sequences are fused or conjugated to amino acid substituted forms of PE. Hence, the examples shown in Table 2 should in no manner be considered limiting with respect to potential therapeutic indications or protein fusions and conjugates of amino acid modified forms of PE, Example Molecule (Nucleotide Accession*) [Protein Potential Accession**] Indications Example Amino Acid Sequence Mesothelin Pancreatic cancer MALPTARPLLGSCGTPALGSLLFLLFSLGWVQPS (NM_013404) Ovarian cancer RTLAGETGQEAAPLDGVLANPPNISSLSPRQLLG [NP_037536] FPCAEVSGLSTERVRELAVALAQKNVKLSTEQLR CLAHRLSEPPEDLDALPLDLLLFLNPDAFSGPOA CTRFFSRITKANVDLLPRGAPERQRLLPAALACW GVRGSLLSEADVRALGGLACDLPGRFVAESAEVL LPRLVSCPGPLDQDQQEAARAALQGGGPPYGPPS TWSVSTMDALRGLLPVLGQPIIRSIPQGIVAAWR QRSSRDPSWRQPERTILRPRFRREVEKTACPSGK KAREIDESLIFYKKWELEACVDAALLATQMDRVN ATPFTYEQLDVLKHKLDELYPQGYPESVIQHLGY LFLKMSPEDIRKWNVTSLETLKALLEVNKGHEMS PQAPRRPLPQVATLIDRFVKGRGQLDKDTLDTLT AFYPGYLCSLSPEELSSVPPSSIWAVRPQDLDTC DPRQLDVLYPKARLAFQNMNGSEYFVKIQSFLGG APTEDLKALSQQNVSMDLATFMKLRTDAVLPLTV AEVQKLLGPHVEGLKAEERHRPVRDWILRQRQDD LDTLGLGLQGGIPNGYLVLDLSMQEALSGTPCLL GPGPVLTVLALLLASTLA (SEQ ID NO: 167) CD24 Liver cancer MGRAMVARLGLGLLLLALLLPTQTYSSETTTGTS (NM_013230) Colorectal cancer SNSSQSTSNSGLAPNPTNATTKAAGGALQSTASL [AAH64619] Pancreatic cancer FWSLSLLHLYS (SEQ ID NO: 168) CD22 Hairy Cell Leukemia VRRAPLSEGPHSLGCYNPMMEDGISYTTLRFPEM (AB013007) Chronic Lymphocytic NIPRTG (SEQ ID NO: 169) [BAA36576] Leukemia Non-Hodgkin′s Lymphoma CD25 a.k.a,  Hodgkin′s MDSYLLMWGLLTFIMVPGCQAELCDDDPPEIPHA Interleukin 2  Lymphoma TFKAMAYKEGTMLNCECKRGFRRIKSGSLYMLCT receptor,  Hairy Cell Leukemia GNSSHSSWDNQCQCTSSATRNTTKQVTPQPEEQK alpha chain  Chronic ERKTTEMQSPMQPVDQASLPGHCREPPPWENEAT (NM_000417)  Lymphocytic ERIYHFVVGQMVYYQCVQGYRALHRGPAESVCKM [NP_000408] Leukemia THGKTRWTQPQLICTGEMETSQFPGEEKPQASPE Cutaneious T-cell GRPESETSCLVTTTDFQIQTEMAATMETSIFTTE Lymphoma YQVAVAGCVFLLISVLLLSGLTWQRRQRKSRRTI Adult T-cell (SEQ ID NO: 170) leukemia CD174 Bladder cancer MDPLGAAKPQWPWRRCLAALLFQLLVAVCFFSYL a.k.a ,  Breast cancer RVSRDDATGSPRAPSGSSRQDTTPTRPTLLILLW Lewis Y,  Colorectal cancer TWPFHIPVALSRCSEMVPGTADCHITADRKVYPQ galactoside  Esophageal cancer ADTVIVHHWDIMSNPKSRLPPSPRPQGQRWIWFN 3(4)-L- Gastric cancer LEPPPNCQHLEALDRYFNLTMSYRSDSDIFTPYG fucosyl- Pancreatic cancer WLEPWSGQPAHPPLNLSAKTELVAWAVSNWKPDS transterase Lung cancer ARVRYYQSLQAHLKVDVYGRSHKPLPKGTMMETL (NM_000149) SRYKFYLAFENSLHPDYITEKLWRNALEAWAVPV [NP_000140] VLGPSRSNYERFLPPDAFIHVDDFQSPKDLARYL QELDKDHARYLSYFRWRETLRPRSFSWALDFCKA CWKLQQESRYQTVRSIAAWFT (SEQ ID NO: 171) TPBG Non small cell lung MPGGCSRGPAAGDGRLRLARLALVLLGWVSSSSF a.k.a,  cancer TSSASSFSSSAPFLASAVSAQPPLPDQCPALCEC oncofetal Renal carcinoma SEAARTVKCVNRNLTEVPTDLPAYVRNLFLTGNQ antigen 5T4,  Pancreatic cancer LAVLPAGAFARRPPLAELAALNLSGSRLDEVRAG 5T4 oncofetal AFEHLPSLRQLDLSHNPLADLSPFAFSGSNASVS trophoblast APSPLVELILNHIVPPEDERQNRSFEGMVVAALL glycoprotein AGRALQGLRRLELASNHFLYLPRDVLAQLPSLRH (NM_006670) LDLSNNSLVSLTYVSFRNLTHLESLHLEDNALKV [CAA09930] LHNGTLAELQGLPHIRVFLDNNPWVCDCHMADMV TWLKETEVVQGKDRLTCAYPEKMRNRVLLELNSA DLDCDPILPPSLQTSYVFLGIVLALIGAIFLLVL YLNRKGIKKWMHNIRDACRDHMEGYHYRYEINAD PRLTNLSSNSDV (SEQ ID NO: 172) CD56 Small cell lung MLQTKDLIWTLFFLGTAVSLQVDIVPSQGEISVG a.k.a, NCAM1, cancer ESKFFLCQVAGDAKDKDISWFSPNGEKLTPNQQR neural cell Merkel cell ISVVWNDDSSSTLTIYNANIDDAGIYKCVVTGED adhesion carcinoma GSESEATVNVKIFQKLMFKNAPTPQEFREGEDAV molecule 1 Ovarian cancer IVCDVVSSLPPTIIWKHKGRDVILKKDVRFIVLS isoform 1 Neuroendocrine NNYLQIRGIKKTDEGTYRCEGRILARGEINFKDI precursor tumors QVIVNVPPTIQARQNIVNATANLGQSVTLVCDAE (NM_000615) Multiple Myeloma GFPEPTMSWTKDGEQIEQEEDDEKYIFSDDSSQL [NP_000606] TIKKVDKNDEAEYICIAENKAGEQDATIHLKVFA KPKITYVENQTAMELEEQVTLTCEASGDPIPSIT WRTSTRNISSEEKTLDGHMVVRSHARVSSLTLKS IQYTDAGEYICTASNTIGQDSQSMYLEVQYAPKL QGPVAVYTWEGNQVNITCEVFAYPSATISWFRDG QLLPSSNYSNTKIYNTPSASYLEVTPDSENDFGN YNCTAVNRIGQESLEFILVQADTPSSPSIDQVEP YSSTAQVQFDEPEATGGVPILKYKAEWRAVGEEV WHSKWYDAKEASMEGIVTIVGLKPETTYAVRLAA LNGKGLGEISAASEFKTQPVQGEPSAPKLEGQMG EDGNSIKVNLIKQDDGGSPIRHYLVRYRALSSEW KPEIRLPSGSDHVMLKSLDWNAEYEVYVVAENQQ GKSKAAHFVFRTSAQPTAIPANGSPTSGLSTGAI VGILIVIFVLLLVVVDITCYFLNKCGLFMCIAVN LCGKAGPGAKGKDMEEGKAAFSKDESKEPIVEVR TEEERTPNHDGGKHTEPNETTPLTEPEKGPVEAK PECQETETKPAPAEVKTVPNDATQTKENESKA (SEQ ID NO: 173) C-type lectin- Acute myeloid MWIDFFTY5SMSEEVTYADLQFQN5SEMEKIPEI like  leukemia GKFGEKAPPAPSHVVRPAALFLTLLCLLLLIGLG molecule-1 VLASMFHVTLKIEMKKMNKLQNISEELQRNISLQ a.k.a.,CLL-1 LMSNMNISNKIRNLSTTLQTIATKLCRELYSKEQ (AY547296)  EHKCKPCPRRWIWHKDSCYFLSDDVQTWQESKMA [AAT11783] CAAQNASLLKINNKNALEFIKSQSRSYDYWLGLS PEEDSTRGMRVDNIINSSAWVIRNAPDLNNMYCG YINRLYVQYYHCTYKQRMICEKMANPVQLGSTYF REA (SEQ ID NO: 174) *″Nucleotide Accession″ refers to the NCBI Reference Sequence accession number associated with the corresponding nucleic acid sequence as found in the ″Nucleotide″ database provided for public access and searching (via the Internet) through the National Center for Biotechnology information, U.S. National Library of Medicine (8600 Rockville Pike, Bethesda MD, 20894 USA (www.ncbi.nlm.nih.gov)). **″Protein Accession″ refers to the NCBI Reference Sequence accession number associated with the corresponding amino acid sequence as found in the ″Protein″ database provided for public access and searching (via the Internet) through the National Center for Biotechnology Information, U.S. National Library of Medicine (8600 Rockville Pike, Bethesda MD, 20894 USA (www.ncbi.nlm.nih,gov)).

In one embodiment, the present invention includes isolated nucleic acids and methods of expressing nucleic acids encoding any of the herein-referenced modified forms of PE, including fusions, conjugates, and otherwise linked molecules; whether such forms are expressed from a single or one more separate polynucleotide sequences; whether such polynucleotide sequences are expressed from a single or one or more separate expression vectors.

Expression Vectors

In one embodiment, the present invention includes methods of making and using recombinant expression vectors to express nucleic acids encoding polypeptides comprising any of the herein-referenced modified forms of PE, including fusions, conjugates, and otherwise linked molecules. Use of a wide variety of expression vectors are well-known and routinely used by those skilled in the art. A few examples of the types of expression vectors which may be used include, but are not limited to: derivatives of human or animal viruses (such as retrovirus, adeno-associated virus, pox, baculovirus, vaccinia, herpes simplex, Epstein-Barr, adenovirus, geminivirus, and caulimovirus vectors) and insect viruses (such as baculovirus); yeast vectors; bacteriophage vectors (e.g., bacteriophage lambda); plasmids; cosmids; artificial chromosomes; liposomes; electrically charged lipids (cytofectins); DNA-protein complexes, and biopolymers.

Gene Delivery and Expression Systems

A wide variety of methods (i.e., gene delivery systems) are available and well-known to those of skill in the art; any of such methods may be used for introducing nucleic acids encoding modified forms of PE into a cell, tissue, or organism for in vitro, in vivo, in situ, or ex vivo expression. The methods referenced below represent examples of ways in which nucleic acid(s) encoding modified forms of PE may be introduced into a cell. These examples are in no way intended to limit the scope of that may be used for gene delivery and expression of modified forms of PE in cells, tissues, or organisms; these examples are presented to illustrate the many available methods.

—Viral-Based Delivery of Target Nucleic Acids—

Gene therapy based methods can be used to deliver (into a host cell, tissue or organism) target nucleic acids encoding modified forms of PE (and other polynucleotides, as needed, to allow expression of the same). As one example, polynucleotides operably encoding the target nucleic acid can be delivered to a tissue or organism either as “naked nucleic acid” or as part of an expression vector. The term vector includes for example, but is not limited to, vectors such as plasmid vectors, cosmid vectors, artificial chromosome vectors, and viral vectors. Some examples of viral vectors include adenovirus, herpes simplex virus (HSV), alphavirus, simian virus 40, picomavirus, vaccinia virus, retrovirus, lentivirus, and adeno-associated virus. Vectors encoding modified forms of PE may be capable of replication in a cell in which it is introduced, or it may be preferred that the vector is not capable of replication. Vectors encoding modified forms of PE may be capable of integration into the genomic DNA of a cell (and subsequent expression therefrom), or it may be preferred that the vector is not capable of integrating into the host genome. An example of a vector that can integrate into the genomic DNA of a cell is a retroviral vector, in which an integrase enzyme mediates integration of the retroviral vector sequences. A vector may also contain transposon sequences that facilitate integration of the coding region into the genomic DNA of a host cell. Liposomes represent another manner in which target DNA may be delivered to a subject.

Selection of a vector depends upon a variety of desired characteristics in the resulting construct, such as a selection marker, vector replication rate, type of target host cell, species of host organism, desired duration of protein expression. An expression vector optionally includes expression control sequences operably linked to the coding sequence such that the coding region is expressed in the cell. The invention is not limited by the use of any particular promoter, and a wide variety is known. Promoters act as regulatory signals that bind RNA polymerase in a cell to initiate transcription of a downstream (3′ direction) operably linked coding sequence. The promoter used in the invention may be a constitutive or an inducible promoter. It can be, but need not be, heterologous with respect to the cell to which it is introduced.

In certain embodiments, adenovirus expression vectors can be used to deliver (into a host cell, tissue or organism) target nucleic acids encoding modified forms of PE (and other polynucleotides, as needed, to allow expression of the same). The terms “adenovirus expression vector” is meant to include those constructs containing nucleic acid sequences sufficient to (a) support packaging of the construct and (b) to ultimately express a recombinant gene construct that has been inserted therein. In contrast to retroviruses, use of adenovirus vectors does not result in chromosomal integration because adenovirus DNA replicates in an episomal manner. Moreover, adenoviruses are considered to be structurally stable with no genome rearrangement occurring even after extensive virus reproduction and amplification. Methods of constructing and using adenovirus vectors as gene delivery systems are well-known to those of skill in the art.

In certain embodiments, adeno-associated virus (AAV) expression vectors can be used to deliver (into a host cell, tissue or organism) target nucleic acids encoding modified forms of PE (and other polynucleotides, as needed, to allow expression of the same). AAV may be desirable for a number or reasons; for example, because AAV vectors exhibit a high frequency of integration, can infect nondividing cells, and have a broad host range. AAV is a dependent parvovirus in that it requires coinfection with another virus (either adenovirus or a member of the herpes virus family) to undergo a productive infection in cultured cells. In the absence of coinfection with helper virus, the wild-type AAV genome integrates through its ends into a human chromosome where it resides as a latent provirus. When a cell containing latent AAV provirus is superinfected with a helper virus, the AAV genome is “rescued” from the chromosome and a normal productive infection is established. Methods of constructing and using AAV vectors as gene delivery systems are well-known to those of skill in the art.

In certain embodiments, retrovirus expression vectors can be used to deliver (into a host cell, tissue or organism) target nucleic acids encoding modified forms of PE (and other polynucleotides, as needed, to allow expression of the same). Retroviruses are a group of single-stranded RNA viruses characterized by the ability to convert their genomic RNA to double-stranded DNA in infected cells through a reverse-transcription process. The resulting DNA stably integrates into cellular chromosomes as a provirus and directs synthesis of viral proteins. Retroviral integration results in the retention of viral gene sequences in the recipient cell and in its descendants. Retroviral vectors are able to infect a broad variety of cell types. Methods of constructing and using retroviruses as gene delivery systems are well-known to those of skill in the art.

Many other expression vectors can also be used to deliver (into a host cell, tissue or organism) target nucleic acids encoding modified forms of PE (and other polynucleotides, as needed, to allow expression of the same). For example, vectors derived from viruses such as vaccinia viruses, herpesviruses, equine encephalitis viruses, hepatitis viruses and lentiviruses can be used. Methods of constructing and using viral expression vectors as gene delivery systems are well-known to those of skill in the art. The examples of such vectors referenced herein are not intended to be limiting with respect to the means by which modified forms of PE may be delivered and expressed in various host cells, tissues, or organisms.

—Non-Viral Delivery of Modified Target Nucleic Acids—

In addition to viral delivery of modified target nucleic acid, the following are additional methods of recombinant gene delivery can be used to deliver (into a host cell, tissue or organism) target nucleic acids encoding modified forms of PE (and other polynucleotides, as needed, to allow expression of the same). Methods of constructing and using non-viral gene delivery systems are well-known to those of skill in the art. See, for example, Al-Dosari et al., “Nonviral gene delivery: principle, limitations, and recent progress,” AAPS Journal, 11(4):671-681 (2009), and references cited therein.

In certain embodiments, electroporation can be used to deliver (into a host cell, tissue or organism) target nucleic acids encoding modified forms of PE (and other polynucleotides, as needed, to allow expression of the same). Methods of using electroporation are well-known to those of skill in the art. See, for example, Bodles-Brakhop et al., “Electroporation for the delivery of DNA-based vaccines and immunotherapeutics: current clinical developments,” Mol. Ther., 17(4):585-592 (2009); and references cited therein. See also, Golzio et al., “Observations of the mechanisms of electromediated DNA uptake—from vesicles to tissues,” Curr Gene Ther., 10(4):256-266 (2010); and references cited therein. See also, Andre et al., “Nucleic acids electrotransfer in vivo: mechanisms and practical aspects,” Curr Gene Ther., 10(4):267-280 (2010), and references cited therein. See also, Wells, “Electroporation and ultrasound enhanced non-viral gene delivery in vitro and in vivo,” Cell Biol Toxicol., 26(1):21-28 (2010); and references cited therein.

In certain embodiments, particle bombardment can be used to deliver (into a host cell, tissue or organism) target nucleic acids encoding modified forms of PE (and other polynucleotides, as needed, to allow expression of the same). This method depends on the ability to accelerate nucleic acid-coated microprojectiles to a sufficient velocity to allow them to pierce cell membranes, thereby delivering nucleic acid “payloads,” without killing them. Some typical microprojectiles consist of biologically inert substances such as tungsten, platinum, and gold beads. Methods of using particle bombardment are well-known to those of skill in the art. See, for example, Klein et al., “Particle bombardment: a universal approach for gene transfer to cells and tissues,” Curr. Opin. Biotechnol., 4(5):583-590 (1993); and references cited therein.

In certain embodiments, a variety of methods incorporating calcium phosphate co-precipitation can be used to deliver (into a host cell, tissue or organism) target nucleic acids encoding modified forms of PE (and other polynucleotides, as needed, to allow expression of the same). Methods of using calcium phosphate co-precipitation are well-known to those of skill in the art. See, for example, Uskoković et al., “Nanosized hydroxyapatite and other calcium phosphates: chemistry of formation and application as drug and gene delivery agents,” J. Biomed. Mater. Res. B Appl. Biomater, 96(1):152-191 (2011), and references cited therein. See also, Colosimo et al., “Transfer and expression of foreign genes in mammalian cells,” Biotechniques, 29(2):314-8, 320-322 (2000); and references cited therein.

In certain embodiments, microinjection and sonication methods can be used to deliver (into a host cell, tissue or organism) target nucleic acids encoding modified forms of PE (and other polynucleotides, as needed, to allow expression of the same). Methods of using microinjection and sonication are well-known to those of skill in the art. See, for example, Rochlitz et al., “Gene therapy of cancer,” Swiss Med. Wkly., 131(1-2):4-9 (2001); and references cited therein. See also, Donnelly et al., “Microneedle-based drug delivery systems: microfabrication, drug delivery, and safety,” Drug Deliv., 17(4):187-207 (2010); and references cited therein. See also. Miller et al., “Sonoporation: mechanical DNA delivery by ultrasonic cavitation”, Somat. Cell Mol. Genet., 27(1-6):115-34 (2002); and references cited therein.

In certain embodiments, liposomes and lipid formulations can be used to deliver (into a host cell, tissue or organism) target nucleic acids encoding modified forms of PE (and other polynucleotides, as needed, to allow expression of the same). Liposomes are vesicular structures characterized by a phospholipid bilayer membrane and an inner aqueous medium. Multilamellar liposomes have multiple lipid layers separated by aqueous medium. They form spontaneously when phospholipids are suspended in an excess of aqueous solution. An example of a commonly used, commercially available lipid formulation is Lipofectamine (Gibco BRL). Methods of using liposomes and lipid formulations to deliver nucleic acids to cells, tissues and organisms are well-known to those of skill in the art. See, for example, Xiong et al., “Cationic liposomes as gene delivery system: transfection efficiency and new application,” Pharmazie, 66(3):158-64 (2011); and references cited therein. See also, Pichon et al., “Chemical vectors for gene delivery: uptake and intracellular trafficking,” Curr Opin Biotechnol., 21(5):640-645 (2010); and references cited therein. See also, Pathak et al., “Recent trends in non-viral vector-mediated gene delivery,” Biotechnol J., 4(11):1559-1572 (2009).

Expression of Modified Forms of PE Via Gene Switch Modulation Systems

Expression of modified forms of PE, including fusions, conjugates, and otherwise linked molecules, may be expressed in host cells, tissues, and organisms using gene switch expression systems. Some examples, without limitation, of such gene expression systems, and genetically engineered cells comprising gene switch expression systems, which can be used to express polynucleotides and polypeptides of the present invention, are described in the following publications; each of which are hereby incorporated by reference herein:

-   WO 2009/045370 (PCT/US2008/011270); -   WO 2009/025866 (PCT/US2008/010040); WO 2002/066614     (PCT/US/2002/005706); -   WO 2008/073154 (PCT/US2007/016747); WO 2002/066613     (PCT/US2002/005090); -   WO 2005/108617 (PCT/US2005/015089); WO 2002/029075     (PCT/US2001/030608); -   WO 2003/0/27289 (PCT/US2002/005026); WO 2001/070816     (PCT/US2001/090500); -   WO 2002/066615 (PCT/US2002/005708); WO 2009/048560     (PCT/US2008/011563); -   WO 2003/027266 (PCT/US/2002/05234); WO 2010/042189     (PCT/US2009/005510); and -   WO 2002/066612 (PCT/US2002/005090); WO 2011/119773     (PCT/US2011/029682).

For purposes of expressing polynucleotides and polypeptides under control of a gene switch mechanism, the term “gene switch” refers to the combination of a response element associated with a promoter, and a ligand-dependent transcription factor-based system which, in the presence of one or more ligands, modulates the expression of a gene into which the response element and promoter are incorporated. Stated otherwise, a “gene switch” refers to a peptide, protein or polypeptide complex that functions to (a) bind an activating ligand, and (b) regulate the transcription of a gene of interest in a ligand-dependent fashion.

In one embodiment, the polynucleotide encoding a gene switch is a recombinant polynucleotide, i.e., a polynucleotide, that has been engineered, by molecular biological manipulation, to encode the gene switch. In another embodiment, the recombinant polynucleotide is a synthetic polynucleotide.

As used herein with respect to gene switch regulation systems, the term “dimerizes with the ligand binding domain that binds an activating ligand” refers to a selective protein-protein interaction that is induced by the presence of activating ligand.

As used herein, the term “ligand binding domain that binds an activating ligand” refers to an amino acid sequence that selectively binds an activating ligand. In the methods disclosed herein, an activating ligand binds to a ligand binding domain, e.g., an ecdysone receptor ligand binding domain, that is part of a ligand-dependent transcriptional activation complex that regulates the expression of a polynucleotide sequence that encodes a gene of interest. Hence, the expression of the gene of interest is regulated in a ligand-dependent fashion.

The term “ecdysone receptor-based,” with respect to a gene switch, refers to a gene switch comprising at least a functional part of a naturally occurring or synthetic ecdysone receptor ligand binding domain and which regulates gene expression in response to a ligand that binds to the ecdysone receptor ligand binding domain.

As used herein, “selective binding” of an activating ligand to a ligand binding domain in a gene switch means that the ligand has an EC50 of about 700 nanomolar (nM), 650 nM, 600 nM, 550 nM, 500 nM, 450 nM, 400 nM, 350 nM, 300 nM, 250 nM, 225 nM, 200 nM, 175 nM, 150 nM, 125 nM, 100 nM, 95 nM, 90 nM, 85 nM, 80 nM, 75 nM 70 nM, 65 nM, 60 nM, 55 nM, 50 nM, 45 nM, 40 nM, 35 nM, 30 nM, 25 nM, 20 nM, 15 nM, 10 nM, 9 nM, 8 nM, 7 nM, 6 nM, 5 nM, 4 nM, 3 nM, 2 nM or 1 nM, or less, in a gene switch assay.

As used herein, “EC50” is the “half maximal effective concentration,” which refers to the concentration of an activating ligand that induces a gene switch-regulated change in expression of a polynucleotide encoding an gene of interest (e.g., modified forms of PE, including fusions, conjugates, et cetera), that is halfway between the baseline level of expression and the maximum level of expression after a specified exposure time. Examples of cellular assays for measuring gene switch-regulated gene expression are well known to those of skill in the art. See, for example, Karzenowski et al., BioTechniques 39: 191-200 (2005).

In one embodiment, the ligand binding domain that binds an activating ligand, e.g., an ecdysone receptor ligand binding domain, dimerizes with another ligand binding domain, e.g., a retinoid X receptor ligand binding domain, to form a protein-protein complex.

In one embodiment, the expression of the gene of interest is regulated by an activating ligand in an on/off fashion that is independent of the concentration or dosage of an activating ligand. In another embodiment, the expression of the gene of interest is regulated by an activating ligand in a concentration (or dosage)-dependent fashion, i.e., there is a dose-response relationship between the concentration (or dosage) of an activating ligand and the level of gene expression of the gene of interest. See, e.g., US Patent Publication No. 2009/0123441 (see also, WO 2009/048560 (PCT/USUS2008/011563)).

The term “operably linked” refers to the association of polynucleotide sequences on a single polynucleotide so that the function of one is affected by the other. For example, a promoter is operably linked with a coding sequence when it is capable of affecting the expression of that coding sequence (i.e., that the coding sequence is under the transcriptional control of the promoter). Coding sequences can be operably linked to regulatory sequences in sense or antisense orientation.

In one embodiment, an activating ligand, or a composition thereof, is administered to a subject orally. In another embodiment, an activating ligand, or a composition thereof, is administered to a subject parenterally. In another embodiment, an activating ligand, or a composition thereof, is administered subcutaneously, intramuscularly, intravenously, intraperitoneally, transdermally, or intratumorally.

In one embodiment the ligand binding domain in the gene switch is a Group H nuclear receptor ligand binding domain, or a mutant thereof that binds an activating ligand. In another embodiment, the Group H nuclear receptor ligand binding domain is selected from the group consisting of an ecdysone receptor ligand binding domain, a ubiquitous receptor ligand binding domain, an orphan receptor-1 ligand binding domain, an NER-1 ligand binding domain, a receptor-interacting protein-15 ligand binding domain, a liver X receptor-3 ligand binding domain, a steroid hormone receptor-like protein ligand binding domain, a liver X receptor ligand binding domain, a liver X receptor ligand binding domain, a farnesoid X receptor ligand binding domain, a receptor-interacting protein-14 ligand binding domain, and a farnesol receptor ligand binding domain ligand binding domain, or a mutant thereof that binds an activating ligand.

In another embodiment, the Group H nuclear receptor ligand binding domain is an ecdysone receptor ligand binding domain, or a mutant thereof that binds an activating ligand. In another embodiment, the ecdysone receptor ligand binding domain is selected from the group consisting of an Arthropod ecdysone receptor ligand binding domain a Lepidopteran ecdysone receptor ligand binding domain, a Dipteran ecdysone receptor ligand binding domain, an Orthopteran ecdysone receptor ligand binding domain, a Homopteran ecdysone receptor ligand binding domain and a Hemipteran ecdysone receptor ligand binding domain, a spruce bud worm Choristoneura fumiferana ecdysone receptor ligand binding domain, a beetle Tenebrio molitor ecdysone receptor ligand binding domain, a Manduca sexta ecdysone receptor ligand binding domain, a Heliothies virescens ecdysone receptor ligand binding domain, a midge Chironomus tentans ecdysone receptor ligand binding domain, a silk moth Bombyx mori ecdysone receptor ligand binding domain, a squinting bush brown Bicyclus anynana ecdysone receptor ligand binding domain, a buckeye Junonia coenia ecdysone receptor ligand binding domain, a fruit fly Drosophila melanogaster ecdysone receptor ligand binding domain, a mosquito Aedes aegypti ecdysone receptor ligand binding domain, a blowfly Lucilia capitata ecdysone receptor ligand binding domain, a blowfly Lucilia cuprina ecdysone receptor ligand binding domain, a blowfly Calliphora vicinia ecdysone receptor ligand binding domain, a Mediterranean fruit fly Ceratitis capitata ecdysone receptor ligand binding domain, a locust Locusta migratoria ecdysone receptor ligand binding domain, an aphid Myzus persicae ecdysone receptor ligand binding domain, a fiddler crab Celuca pugilator ecdysone receptor ligand binding domain, an ixodid tick Amblyomma americanum ecdysone receptor ligand binding domain, a whitefly Bamecia argentifoli ecdysone receptor ligand binding domain, a leafhopper Nephotetix cincticeps ecdysone receptor ligand binding domain, or a mutant thereof that binds An activating ligand.

In another embodiment, the ecdysone receptor ligand binding domain is a spruce budworm Choristoneura fumiferana ecdysone receptor ligand binding domain, for which the amino acid sequence is: Leu Thr Ala Asn Gln Gln Phe Leu Ile Ala Arg Leu Ile Trp Tyr Gln Asp Gly Tyr Glu Gln Pro Ser Asp Glu Asp Leu Lys Arg Ile Thr Gln Thr Trp Gln Gln Ala Asp Asp Glu Asn Glu Glu Ser Asp Thr Pro Phe Arg Gln Ile Thr Glu Met Thr Ile Leu Thr Val Gln Leu Ile Val Glu Phe Ala Lys Gly Leu Pro Gly Phe Ala Lys Ile Ser Gln Pro Asp Gln Ile Thr Leu Leu Lys Ala Cys Ser Ser Glu Val Met Met Leu Arg Val Ala Arg Arg Tyr Asp Ala Ala Ser Asp Ser Val (position 107) Leu Phe Ala Asn Asn Gln Ala Tyr Thr Arg Asp Asn Tyr Arg Lys Ala Gly Met ala Tyr (position 127) Val Ile Glu Asp Leu Leu His Phe Cys Arg Cys Met Tyr Ser Met ala Leu Asp Asn Ile His Tyr Ala Leu Leu Thr Ala Val Val Ile Phe Ser Asp Arg Pro Gly Leu Glu Gln Pro Gln Leu Val Glu Glu Ile Gln Arg Tyr Tyr Leu Asn Thr Leu Arg Ile Tyr Ile Leu Asn Gln Leu Ser Gly Ser Ala Arg Ser Ser Val Ile Tyr Gly Lys Ile Leu Ser Ile Leu Ser Glu Leu Arg Thr Leu Gly Met Gln Asn Ser Asn Met Cys Ile Ser Leu Lys Leu Lys Asn Arg Lys Leu Pro Pro Phe Leu Glu Glu Ile Trp Asp Val (SEQ ID NO:1), which is also set forth as SEQ NO:1 in U.S. Patent Publication No. 2006/0100416 A1 (see also, WO 2002/066612 (PCT/US2002/005090)).

Exemplary ecdysone receptor ligand binding domains include those disclosed, for example, in U.S. Pat. No. 7,935,510 (see also, WO 2003/0/27289 (PCT/US2002/005026)); U.S. Pat. No. 7,919,269 (see also, WO 2003/027266 (PCT/US/2002/05234)); U.S. Pat. No. 7,563,879 (see also, WO 2003/0/27289 (PCT/US2002/005026)); and in U.S. Patent Publication No. 2006/0100416 A1 (see also, WO 2002/066612 (PCT/US2002/005090)), each of which is hereby incorporated by reference in its entirety.

In one embodiment, the ecdysone receptor ligand binding domain is a mutant of an ecdysone receptor ligand binding domain that binds the activating compound. In another embodiment, the ecdysone receptor ligand binding domain is a mutant of the spruce budworm Choristoneura fumiferana ecdysone receptor ligand binding domain that binds the activating compound.

In one embodiment, the gene switch comprises a Choristoneura fumiferana ecdysone receptor ligand binding domain that is engineered to contain the mutations V107I and Y127E of the Choristoneura fumiferana ecdysone receptor sequence as set forth in SEQ ID NO:1 of U.S. Patent Publication No. 2006/0100416 (see also, WO 2002/066612 (PCT/US2002/005090)). The term “V107I” means that the valine amino acid residue at position 107 (a as set forth in SEQ ID NO:1 of U.S. Patent Publication No. 2006/0100416) is changed to isoleucine. The term “Y127E” means that the tyrosine amino acid residue at position 127 (as set forth in SEQ ID NO:1 of U.S. Patent Publication No. 2006/0100416) is changed to glutamate.

Exemplary mutant ecdysone receptor ligand binding domains are disclosed, for example, in US 2006/0100416 A1 (see also, WO 2002/066612 (PCT/US2002/005090)) and U.S. Pat. No. 7,935,510 (Pub. No. 2005/0266457) (see also, WO 2005/108617 (PCT/US2005/015089)) each of which is incorporated by reference in its entirety.

In one embodiment, the gene switch comprises a ligand binding domain that dimerizes with the ligand binding domain that binds an activating ligand. In one embodiment, the ligand binding domain that dimerizes with the ligand binding domain that binds an activating ligand is a Group B nuclear receptor ligand binding domain. In another embodiment, the Group B nuclear receptor ligand binding domain is selected from the group consisting of a retinoid X receptor ligand binding domain, an H-2 region II binding protein ligand binding domain, a nuclear receptor co-regulator-1 ligand binding domain, an ultraspiracle protein ligand binding domain, a 2C1 nuclear receptor ligand binding domain, and a chorion factor 1 ligand binding domain. In another embodiment, a ligand binding domain that dimerizes with the ligand binding domain that binds an activating ligand is not an ecdysone receptor ligand binding domain.

In one embodiment, the ligand binding domain that dimerizes with the ligand binding domain that binds an activating ligand is a retinoic X receptor ligand binding domain. In another embodiment, the retinoic X receptor ligand binding domain is a vertebrate retinoic X receptor ligand binding domain. In another embodiment, the retinoic X receptor ligand binding domain is a Homo sapiens retinoic X receptor ligand binding domain. In another embodiment, the retinoic X receptor ligand binding domain is a retinoic X receptor α isoform. In another embodiment, the retinoic X receptor ligand binding domain is a retinoic X receptor β isoform. In another embodiment, the retinoic X receptor ligand binding domain is a retinoic X receptor γ isoform.

In another embodiment, the retinoic X receptor ligand binding domain is an invertebrate retinoic X receptor ligand binding domain. In another embodiment, the invertebrate retinoic X receptor ligand binding domain is a Locusta migratoria retinoic X receptor ligand binding domain.

In another embodiment, the invertebrate retinoic X receptor ligand binding domain is a non-Lepidopteran, non-Dipteran retinoic X receptor ligand binding domain.

In one embodiment, the retinoid receptor ligand binding domain is a vertebrate retinoid X receptor ligand binding domain, an invertebrate retinoid X receptor ligand binding domain, an ultraspiracle protein ligand binding domain, or a chimeric retinoid X receptor ligand binding domain.

In one embodiment, the chimeric retinoid X receptor ligand binding domain comprises two polypeptide fragments, wherein the first polypeptide fragment is from a vertebrate retinoid X receptor ligand binding domain, an invertebrate retinoid X receptor ligand binding domain, or an ultraspiracle protein ligand binding domain, and the second polypeptide fragment is from a different vertebrate retinoid X receptor ligand binding domain, a different invertebrate retinoid X receptor ligand binding domain, or a different ultraspiracle protein ligand binding domain.

In another embodiment, the chimeric retinoid X receptor ligand binding domain is one that is disclosed in U.S. Pat. No. 7,531,326, which is hereby incorporated by reference in its entirety.

In another embodiment, the first polypeptide fragment of the chimeric retinoid X receptor ligand binding domain comprises helices 1-6, helices 1-7, helices 1-8, helices 1-9, helices 1-10, helices 1-11, or helices 1-12 of a first species of retinoid X receptor, and the second polypeptide fragment of the chimeric retinoid X receptor ligand binding domain comprises helices 7-12, helices 8-12, helices 9-12, helices 10-12, helices 11-12, helix 12, or F domain of a second species of retinoid X receptor, respectively.

In another embodiment, the first polypeptide fragment of the chimeric retinoid X receptor ligand binding domain comprises helices 1-6 of a first species RXR according to the disclosure, and the second polypeptide fragment of the chimeric retinoid X receptor ligand binding domain comprises helices 7-12 of a second species of retinoid X receptor.

In another embodiment, the first polypeptide fragment of the chimeric retinoid X receptor ligand binding domain comprises helices 1-7 of a first species retinoid X receptor according to the disclosure, and the second polypeptide fragment of the chimeric retinoid X receptor ligand binding domain comprises helices 8-12 of a second species retinoid X receptor.

In another embodiment, the first polypeptide fragment of the chimeric retinoid X receptor ligand binding domain comprises helices 1-8 of a first species of retinoid X receptor, and the second polypeptide fragment of the chimeric retinoid X receptor ligand binding domain comprises helices 9-12 of a second species of retinoid X receptor.

In another embodiment, the first polypeptide fragment of the chimeric retinoid X receptor ligand binding domain comprises helices 1-9 of a first species of retinoid X receptor, and the second polypeptide fragment of the chimeric retinoid X receptor ligand binding domain comprises helices 10-12 of a second species of retinoid X receptor.

In another embodiment, the first polypeptide fragment of the chimeric retinoid X receptor ligand binding domain comprises helices 1-10 of a first species of retinoid X receptor, and the second polypeptide fragment of the chimeric retinoid X receptor ligand binding domain comprises helices 11-12 of a second species of retinoid X receptor.

In another embodiment, the first polypeptide fragment of the chimeric retinoid X receptor ligand binding domain comprises helices 1-11 of a first species of retinoid X receptor, and the second polypeptide fragment of the chimeric retinoid X receptor ligand binding domain comprises helix 12 of a second species of retinoid X receptor.

In another preferred embodiment, the first polypeptide fragment of the chimeric retinoid X receptor ligand binding domain comprises helices 1-12 of a first species of retinoid X receptor, and the second polypeptide fragment of the chimeric retinoid X receptor ligand binding domain comprises an F domain of a second species of retinoid X receptor.

In one embodiment, the first polypeptide fragment in the chimeric retinoid X receptor ligand binding domain is human retinoid X receptor sequence, and the second polypeptide fragment in the chimeric retinoid X receptor ligand binding domain is invertebrate retinoid X receptor sequence. In another embodiment, the invertebrate retinoid X receptor sequence is Locusta migratoria retinoid X receptor sequence.

In another embodiment, the first polypeptide fragment of the chimeric retinoid X receptor ligand binding domain comprises helices 1-8 of a human retinoid X receptor, and the second polypeptide fragment of the chimeric retinoid X receptor ligand binding domain comprises helices 9-12 of Locusta migratoria retinoid X receptor.

In one embodiment, the gene switch further comprises a DNA binding domain (“DBD”). In another embodiment, the DBD is selected from the group consisting of a GAL4 DBD, a LexA DBD, a transcription factor DEM), a steroid/thyroid hormone nuclear receptor superfamily member DBD, a bacterial LacZ DBD, and a yeast DBD.

In one embodiment, the gene switch further comprises a transactivation domain (“TD”). In another embodiment, the transactivation domain is selected from the group consisting of a VP16 TD, a GAL4 TD, an NF-κB TD, a BP64 TD, and a B42 acidic TD.

In one embodiment, a DNA binding domain, the ligand binding domain that binds an activating ligand, a ligand binding domain that dimerizes with the ligand binding domain that binds an activating ligand, and a transactivation domain are encoded by polynucleotide sequences that are contained in the same polynucleotide.

In another embodiment, a DNA binding domain, a ligand binding domain that binds an activating ligand, a ligand binding domain that dimerizes with the ligand binding domain that binds an activating ligand, and a transactivation domain are encoded by polynucleotide sequences that are contained in two or more separate polynucleotide sequences.

In another embodiment, a DNA binding domain, a ligand binding domain that binds an activating ligand, a ligand binding domain that dimerizes with the ligand binding domain that binds an activating ligand, and a transactivation domain are encoded by polynucleotide sequences that are contained in two separate polynucleotide sequences.

In another embodiment, a DNA binding domain and a ligand binding domain that binds an activating ligand are encoded by polynucleotide sequences that are contained in a first polynucleotide sequence, and a ligand binding domain that dimerizes with the ligand binding domain that binds an activating ligand and a transactivation domain are encoded by polynucleotide sequences that are contained in a second polynucleotide sequence.

In another embodiment, a DNA binding domain and a ligand binding domain that dimerizes with the ligand binding domain that binds an activating ligand are encoded by polynucleotide sequences that are contained in a first polynucleotide sequence, and a ligand binding domain that binds an activating ligand and a transactivation domain are encoded by polynucleotide sequences that are contained in a second polynucleotide sequence.

In embodiments in which one or more of the DNA binding domain, a ligand binding domain that binds an activating ligand, a ligand binding domain that dimerizes with the ligand binding domain that binds an activating ligand, and a transactivation domain are encoded by polynucleotide sequences that are contained in one or more separate polynucleotide sequences, then the one or more separate polynucleotide sequences are operably linked to one or more separate promoters. In another embodiment, the one or more separate polynucleotide sequences are operably linked to one or more separate enhancer elements. In another embodiment, the promoter(s) and/or the enhancer(s) are constitutively active. In another embodiment, the promoter(s) and/or the enhancer(s) are tissue specific promoters and/or enhancers.

In one embodiment, the gene switch comprises a DNA binding domain, an ecdysone receptor ligand binding domain, a ligand binding domain that dimerizes with the ecdysone receptor ligand binding domain, and a transactivation domain.

In another embodiment, the gene switch comprises a DNA binding domain, an ecdysone receptor ligand binding domain, a retinoid X receptor ligand binding domain, and a transactivation domain.

In another embodiment, the gene switch comprises a DNA binding domain, an ecdysone receptor ligand binding domain, a chimeric vertebrate/invertebrate retinoid X receptor ligand binding domain, and a transactivation domain.

In another embodiment, the gene switch comprises a GAL4 DNA binding domain, a Choristoneura fumiferana ecdysone receptor ligand binding domain that is engineered to contain the mutations V107I and Y127E of the Choristoneura fumiferana ecdysone receptor sequence set forth in SEQ ID NO:1, a chimeric Homo sapiens/Locusta migratoria retinoid X receptor ligand binding, and a VP16 transactivation domain.

In another embodiment, the host cell further comprises a polynucleotide encoding a peptide, protein or polypeptide whose expression is regulated by the gene switch. A promoter that binds the gene switch complex is operably linked to the polynucleotide encoding a peptide, protein or polypeptide whose expression is regulated by the gene switch.

In another embodiment, the polynucleotide encoding a peptide, protein or polypeptide whose expression is regulated by the gene switch is contained in the same polynucleotide as a polynucleotide that encodes one or more of a DNA binding domain, the ligand binding domain that binds an activating ligand, a ligand binding domain that dimerizes with the ligand binding domain that binds an activating ligand, and a transactivation domain. Such constructs are disclosed, for example, in U.S. Patent Publication No. 2009/0123441 (see also, WO 2009-048560 (PCT/USUS2008/011563)).

In another embodiment, the polynucleotide encoding a peptide, protein or polypeptide whose expression is regulated by the gene switch is contained in a different nucleic acid molecule than a nucleic acid molecule that encodes one or more of a DNA binding domain, the ligand binding domain that binds an activating ligand, a ligand binding domain that dimerizes with the ligand binding domain that binds an activating ligand, and a transactivation domain.

In one embodiment, the gene switch is more sensitive to an activating ligand than to a steroid hormone. In another embodiment, the gene switch is more sensitive to an activating ligand than to another diacylhydrazine compound.

The sensitivity of a gene switch to an activating ligand, relative to another ligand, can readily be determined in an in vitro assay, for example, an in vitro assay that employs a reporter gene, such as firefly Luciferase. Examples of such in vitro assays are well known to those of ordinary skill in the art. See, for example, Karzenowski et al., BioTechniques 39: 191-200 (2005).

In one embodiment, the polynucleotide encoding the gene switch is contained in a vector. In one embodiment, the vector selected from the group consisting of a plasmid, an expression vector, a replicon, a phage vector, a cosmid, a viral vector, a liposome, an electrically charged lipid (e.g., a cytofectin), a DNA-protein complex, and a biopolymer.

In another embodiment, the vector is a retroviral vector. In another embodiment, the vector is selected from the group consisting of an adeno-associated viral vector, a pox viral vector, a baculoviral vector, a vaccinia viral vector, a herpes simplex viral vector, an Epstein-Barr viral vector, an adenoviral vector, a gemini viral vector, and a caulimo viral vector.

In one embodiment, a composition of the invention comprises one or more polynucleotides that encode two or more orthogonal gene switches. Two or more individually operable gene regulation systems are said to be “orthogonal” when (a) modulation of each of the given gene switches by its respective ligand results in a measurable change in the magnitude of expression of the gene that is regulated by that gene switch, and (b) the change is statistically significantly different than the change in expression of all other gene switches that are in the host cell. In one embodiment, regulation of each individually operable gene switch system effects a change in gene expression at least 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, 20-fold, 50-fold, 70-fold, 100-fold, 200-fold, 300 fold, 400-fold or 500-fold greater than all of the other operable gene switches in the host cell. Non-limiting examples of orthogonal gene switch systems are set forth in U.S. Pat. No. 8,105,825 (Publication No. US 2002/0110861 A1).

As used herein, an “activating ligand” is a compound that binds selectively to the ligand binding domain of a gene switch.

In one embodiment, the activating ligand is administered to the subject within an hour of the time at which the priming dosage is administered to the subject. In another embodiment, the activating ligand is administered to the subject within about 24, 48, 96, 120, 144 or 168 hours of the time at which the priming dosage is administered to the subject. In another embodiment, the activating ligand is administered to the subject within about 1, 2, 3, 4 or 5 weeks of the time at which the priming dosage is administered to the subject.

In one embodiment, the activating ligand is administered to the subject within an hour of the time at which the first of the at least one boosting dosage is administered to the subject. In another embodiment, the activating ligand is administered to the subject within about 24, 48, 96, 120, 144 or 168 hours of the time at which the first of the at least one boosting dosage is administered to the subject. In another embodiment, the activating ligand is administered to the subject within about 1, 2, 3, 4 or 5 weeks of the time at which the first of the at least one boosting dosage is administered to the subject.

In another embodiment, a composition of the invention is contained within a container. In one embodiment, the container is a vial. In another embodiment the container is a multiple-use vial. In another embodiment, the container displays an expiration date for the composition. In another embodiment, the container contains instructions for using the composition.

In one embodiment, a composition of the invention is a unit dosage composition. In one embodiment, a unit dosage composition is a composition that is manufactured to supply a single dosage of the composition of the invention. In another embodiment, the unit dosage composition is manufactured to provide more than one measured dosages of the composition of the invention.

The present application also provides an article of manufacture comprising more than one of the unit dosage compositions of the invention. In one embodiment, the article of manufacture is a container. In another embodiment, the article of manufacture is a box. In another embodiment, the article of manufacture displays an expiration date for the unit dosage composition.

The present invention also provides a kit comprising more than one of the composition or unit dosage of the present invention. In one embodiment, the kit displays an expiration date for the composition or unit dosage. In another embodiment, the kit displays and/or or contains instructions for using the composition or unit dosage. In another embodiment, the kit also comprises an activating ligand that binds to the ligand binding domain of the gene switch encoded by the polynucleotide in the composition or unit dosage.

The present invention also provides a drug label for the composition or unit dosage of the present invention. In one embodiment, the drug label displays an expiration date for the composition or unit dosage. In another embodiment, the drug label displays instructions for using the composition or unit dosage. In another embodiment, the drug label displays the approved indication(s) for the composition or unit dosage. In another embodiment, the said label is in paper form. In another embodiment, the drug label is in digital or computer-readable form.

The term “activating ligand” as used herein refers to a compound that shows activity as an ecdysone receptor agonist, i.e., a compound that is able to mimic 20-hydroxyecdysone biological activity, and binds to a gene switch ligand binding domain. Activating ligands for use in the present invention include both ecdysteroids and non-steroidal compounds, e.g., tebufenozide and methoxyfenozide.

In one embodiment, the activating ligand is an ecdysone receptor agonist disclosed in U.S. Pat. No. 8,076,517 (Publication No. 2009/0163592), No. 2009/0298175, No. 2005/0228016 and in U.S. Pat. No. 6,258,603, U.S. Pat. No. 7,375,093, No. 7,456,315, No. 7,304,161, and No. 7,304,162; each of which are hereby incorporated by reference herein.

In certain embodiments, the activating ligand is a compound having Formula I:

wherein:

A is alkoxy, arylalkyloxy, aryloxy, arylalkyl, optionally substituted aryl or optionally substituted heteroaryl;

B is optionally substituted aryl or optionally substituted heteroaryl;

E is CR¹R²R³;

R¹ is optionally substituted alkyl, arylalkyl, hydroxyalkyl, haloalkyl, optionally substituted cycloalkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted heterocycle, optionally substituted aryl or optionally substituted heteroaryl; and

R² and R³ are independently hydrogen, optionally substituted alkyl, arylalkyl, hydroxyalkyl, haloalkyl, optionally substituted cycloalkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted heterocycle, optionally substituted aryl or optionally substituted heteroaryl; or

R¹ and R² taken together form an optionally substituted alkenyl group.

In one embodiment, the activating ligand is a compound having Formula I:

wherein:

A is selected from the group consisting of 2,3,6-tri-F-phenyl-; 2,3-di-CH₃-phenyl-; 2,6-di-F-phenyl-; 2-Br, 3,4-ethylenedioxy-phenyl-; 2-CH═CH₂, 3-OCH₃-phenyl-; 2-CH₂CH₃, 3,4-ethylenedioxy-phenyl-; 2-CH₂CH₃, 3-OCH₃-phenyl-; 2-CH₂Cl, 3-OCH₃-phenyl-; 2-CH₂F, 3-OCH₃-phenyl-; 2-CH₂NHCH₃, 3-OCH₃-phenyl-; 2-CH₂NMe₂, 3-OCH₃-phenyl-; 2-CH₂OAc, 3-OCH₃-phenyl-; 2-CH₂OCH₂CH═CH₂, 3-OCH₃-phenyl-; 2-CH₂OH, 3-OCH₃-phenyl-; 2-CH₂OMe, 3-OCH₃-phenyl-; 2-CH₂OMe, 3-OMe-phenyl-; 2-CH₂S(O)₂CH₃, 3-OCH₃-phenyl-; 2-CH₂S(O)CH₃, 3-OCH₃-phenyl-; 2-CH₂SCH₃, 3-OCH₃-phenyl-; 2-CH₃, 3,4-ethylenedioxy-phenyl-; 2-CH₃, 3,4-OCH₂O-phenyl-; 2-CH₃, 3-Ac-phenyl-; 2-CH₃, 3-CH₂CH₂CH₂O-4-phenyl-; 2-CH₃, 3-CH₃-phenyl-; 2-CH₃, 3-Cl-phenyl-; 2-CH₃, 3-Et-phenyl-; 2-CH₃, 3-I-phenyl-; 2-CH₃, 3-NMe₂-phenyl-; 2-CH₃, 3-NO₂-phenyl-; 2-CH₃, 3-OAc-phenyl-; 2-CH₃, 3-OCF₃-phenyl-; 2-CH₃, 3-OCH₂OCH₂-4-phenyl-; 2-CH₃, 3-OCH₃-phenyl-; 2-CH₃, 3-OH-phenyl-; 2-CH₃, 3-Oi-Pr-phenyl-; 2-CH₃, 3-OMe-phenyl-; 2-CH₃, 4,5-methylenedioxy-phenyl-; 2-CH₃-3-OCH₃-phenyl-; 2-Cl 4,5-methylenedioxy-phenyl-; 2-Cl, 3-CH₂OCH₂O-4-phenyl-; 2-Cl, 3-CH₂OCH₂O-4-phenyl-; 2-Cl, 3-OMe-phenyl-; 2-Et, 3,4-ethylenedioxy-phenyl-; 2-Et, 3,4-OCH(CH₃)O-phenyl-; 2-Et, 3,4-OCH₂O-phenyl-; 2-Et, 3-OCH₃-phenyl-; 2-F, 3,4-CH₂OCH₂O-phenyl-; 2-F, 4-CH₂CH₃-phenyl-; 2-F, 4-Et-phenyl-; 2-I, 3-OMe-phenyl-; 2-NH₂, 3-OMe-phenyl-; 2-NO₂, 3-OMe-phenyl-; 2-Vinyl, 3-OMe-phenyl-; 3,4-(CH₂)₄-phenyl-; 3,4-di-Et-phenyl-; 3,4-ethylenedioxy-phenyl-; 3,4-OCF₂O-phenyl-; 3,4-OCH(CH₃)O-phenyl-; 3,4-OCH₂O-phenyl-; 3-Cl, 4-Et-phenyl-; 3-NH—C═C-4-phenyl-; 3-OCH(CH₃)CH₂O-4-phenyl-; 3-OCH₃, 4-CH₃-phenyl-; 3,4-S—C═N-phenyl-; 4-Br-phenyl-; 4-C(O)CH₃-phenyl-; 4-CH(OH)CH₃-phenyl-; 4-CH₂CH₃-phenyl-; 4-CH₂CN-phenyl-; 4-CH₃-phenyl-; 4-Cl-phenyl-; 4-Et-phenyl-; 4-OCH₃-phenyl-; phenyl-; and benzo[1,2,5]oxadiazole-5-yl;

B is selected from the group consisting of 1-trityl-5-benzimidazolyl-; 3-trityl-5-benzimidazolyl-; 1H-indazole-3-yl-; 1-methyl-1H-indole-2-yl-; 1-methyl-2-oxo-6-trifluoromethyl-3-pyridyl-; 1-trityl-1H-indazole-3-yl-; 2,3,4,5-phenyl-; 2,3,4,5-tetra-F-phenyl-; 2,3,4-F-phenyl-; 2,3-F-phenyl-; 2,3-OCH₂O-phenyl-; 2,4,5-F-phenyl-; 2,4-di-Cl-5-F-phenyl-; 2,5-di-OCH₃-phenyl-; 2,5-F-phenyl-; 2,6-di-Cl-4-pyridyl-; 2,6-dimethoxy-4-pyrimidinyl2,6-di-OCH₃-3-pyridyl2,6-F-phenyl-; 2-Cl, 5-NO₂-phenyl-; 2-Cl-3-pyridyl2-Cl-4-F-phenyl-; 2-Cl-5-CH₃-phenyl-; 2-Cl-6-CH₃-4-pyridyl-; 2-Et-phenyl-; 2-F, 4-Cl-phenyl-; 2-F, 5-CH₃-phenyl-; 2-methoxy-6-trifluoromethyl-3-pyridyl-; 2-NO₂-3,5-di-OCH₃, 4-CH₃-phenyl-; 2-NO₂-4-Cl-phenyl-; 2-NO₂-5-CH₃-phenyl-; 2-NO₂-5-Cl-phenyl-; 2-NO₂-5-F-phenyl-; 2-NO₂-phenyl-; 2-OCH₂CF₃, 5-OCH₃-phenyl-; 2-OCH₃-3-pyridyl2-OCH₃-4-CH₃-phenyl-; 2-OCH₃-4-Cl-phenyl-; 2-OCH₃-4-F-phenyl-; 2-OCH₃-5-CH₃-phenyl-; 2-OCH₃-5-Cl-phenyl-; 2-OCH₃-phenyl-; 2-S(O)CH₃-phenyl-; 2-SO₃H-phenyl-; 3,4,5-F-phenyl-; 3,4,5-tri-OCH₃-phenyl-; 3,4-di-CH₃-5-Cl-phenyl-; 3,4-F-phenyl-; 3,4-methylenedioxy-phenyl-; 3,5-di(CH₂OH)-phenyl-; 3,5-di-CH₃-4-Cl-phenyl-; 3,5-di-CH₃-phenyl-; 3,5-di-Cl-4-F-phenyl-; 3,5-di-Cl-phenyl-; 3,5-di-CO₂H-phenyl-; 3,5-di-F-phenyl-; 3,5-di-OCH₃, 4-CH₃-phenyl-; 3,5-di-OCH₃-4-OAc-phenyl-; 3,5-di-OCH₃-phenyl-; 3,6-dichloro-4-pyridazinyl-; 3,6-dimethoxy-4-pyridazinyl-; 3-Br-phenyl-; 3-CF₃, 5-F-phenyl-; 3-CF₃-4-F-phenyl-; 3-CF₃-4-F-phenyl3-CF₃-phenyl-; 3-CH═NNHCOCONH₂, 5-CH₃-phenyl-; 3-CH═NNHCONH₂, 5-CH₃-phenyl-; 3-CH═NOH, 5-CH₃-phenyl-; 3-CH₂OAc, 5-CH₃-phenyl-; 3-CH₃, 5-Br-phenyl-; 3-CH₃, 5-CH₃-phenyl-; 3-CH₃, 5-Cl-phenyl-; 3-CH₃-4-Br-phenyl-; 3-CH₃-phenyl-; 3-chloro-6-methylsulfanyl-pyrazine-2-yl-; 3-Cl, 5-Br-phenyl-; 3-Cl, 5-Cl-phenyl-; 3-Cl-5-OCH₃-4-pyridyl-; 3-Cl-phenyl-; 3-CN-phenyl-; 3-F, 5-F-phenyl-; 3-F-phenyl-; 3-NO₂-phenyl-; 3-OCH₃-4-CH₃-phenyl-; 3-OCH₃-4-pyridyl-; 3-OCH₃-phenyl-; 3-OMe, 5-CH₃-phenyl-; 3-OMe, 5-OMe-phenyl-; 3-oxo-6-methoxy-4-pyridazinyl-; 4,6-dimethyl-pyridyl-; 4-CH₃-phenyl-; 4-F-phenyl-; 4-pyridazinyl-, 5-benzimidazolyl-; 5-methoxycarbonyl-2-pyridyl-; 5-methyl-1-phenyl-1H-pyrazole-3-yl-; 5-methyl-pyrazine-2-yl-; 6-CH₃-2-pyridyl-; phenyl-; and pyrazine-2-yl; and

E is selected from the group consisting of C(CH₃)₂C(O)OEt; C(CH₃)₂CH═NCH₂CH₂OH; C(CH₃)₂CH═NNHC(O)C(O)NH₂; C(CH₃)₂CH═NNHC(O)NH₂; C(CH₃)₂CH═NOH; C(CH₃)₂CH₂OC(O)CH₃; C(CH₃)₂CH₂OCH₃; C(CH₃)₂CH₂OH; C(CH₃)₂CH₂OSi(CH₃)₂tBu; C(CH₃)₂CHO; C(CH₃)₂CN; C(CH₃)₂COOH; CH(CH₃)C(CH₃)₃; CH(Et)(n-Bu); CH:(Et)(t-Bu;) CH(n-Bu)(t-Bu); CH(n-Pr)(t-Bu); CH(Ph)(t-Bu); and t-Bu.

In another embodiment, the activating ligand is a compound having Formula I wherein A, B, and E are defined according to Table 3.

TABLE 3 Ligand Components A B E 4-Cl—Ph Ph t-Bu 4-Et—Ph 2-NO₂—Ph t-Bu 4-CH₃—Ph 3-CH₃, 5-CH₃—Ph t-Bu 4-Et—Ph 3-CH₃, 5-CH₃—Ph t-Bu 2,6-di-F—Ph 3-Cl, 5-Cl—Ph t-Bu 2-CH₃, 3-Cl—Ph 3-Cl—Ph t-Bu 2-Cl, 3-OMe—Ph 2-Cl-5-CH₃—Ph t-Bu 2-CH₃, 3-Cl—Ph 3-CH₃-4-Br—Ph t-Bu 4-Et—Ph 3,5-di-CH₃-4-Cl—Ph t-Bu 4-Et—Ph 3,4-di-CH₃-5-Cl—Ph t-Bu 4-OCH₃—Ph 2-Cl-4-F—Ph t-Bu 4-Et—Ph 3-CH₃, 5-Cl—Ph t-Bu 4-Et—Ph 2-Et—Ph t-Bu 4-OCH₃—Ph 3-Cl, 5-Cl—Ph t-Bu 4-Et—Ph 2-NO₂-5-CH₃—Ph t-Bu 4-CH₂CN—Ph 3-CH₃, 5-CH₃—Ph t-Bu 2-CH₃, 3-OMe—Ph 3-CH₃—Ph t-Bu 4-Br—Ph 3-Cl, 5-Cl—Ph t-Bu 2-CH₃, 3-NO₂—Ph 3-CH₃, 5-CH₃—Ph t-Bu 2-CH₃, 3-CH₃—Ph 2,5-di-OCH₃—Ph t-Bu 2-CH₃, 3-CH₃—Ph 2-OCH₃-5-Cl—Ph t-Bu 2-NO₂, 3-OMe—Ph 3-CH₃, 5-CH₃—Ph t-Bu 2-CH₃, 3-CH₃—Ph 3-OMe, 5-OMe—Ph t-Bu 3-Cl, 4-Et—Ph 3-CH₃, 5-CH₃—Ph t-Bu 4-CH(OH)CH₃—Ph 3-F, 5-F—Ph t-Bu 2-CH₃, 3-NMe₂—Ph 3-Cl, 5-Cl—Ph t-Bu 2-CH₃, 3-Ac—Ph 3-CH₃, 5-CH₃—Ph t-Bu 2-CH₃, 3-OAc—Ph 3-CH₃, 5-CH₃—Ph t-Bu 2-CH₃, 3-I—Ph 3-CH3, 5-CH₃—Ph t-Bu 2-CH₃, 3-OMe—Ph 3-Cl, 5-Br—Ph t-Bu 2-CH₃, 3-Oi-Pr—Ph 3-CH₃, 5-CH₃—Ph t-Bu 2-CH₃, 3-OCH3—Ph 2-Cl-3-pyridyl t-Bu 2-CH₃, 3-OMe—Ph 2-OCH₃-5-CH₃—Ph t-Bu 2-CH₃, 3-OMe—Ph 2,5-F—Ph t-Bu 2-CH₃, 3-OMe—Ph 2-Et—Ph t-Bu 2-CH₃, 3-OMe—Ph 3-CH₃, 5-Br—Ph t-Bu 2-CH₃, 3-OMe—Ph 3-OMe, 5-CH₃—Ph t-Bu 2-CH₃, 3-OMe—Ph 2-OCH₃-4-Cl—Ph t-Bu 2-CH₃, 3-OCF₃—Ph 3-CH₃, 5-CH₃—Ph t-Bu 2-CH₃, 3-OMe—Ph 3-OCH₃-4-CH₃—Ph t-Bu 3-OCH₃, 4-CH3—Ph 3-CH₃, 5-CH₃—Ph t-Bu 2-CH₃, 3-OMe—Ph 2-OCH₃-4-CH₃—Ph t-Bu 2-CH₃, 3-OCH₃—Ph 2,6-di-Cl-4-pyridyl t-Bu 2-CH₃, 3-OMe—Ph 2-NO₂-5-CH₃—Ph t-Bu 2-CH₃, 3-OMe—Ph 2-F-4-Cl—Ph t-Bu 3,4-OCH₂O—Ph 2-Cl-4-F—Ph t-Bu 2-Et, 3-OMe—Ph 3-CH₃, 5-CH₃—Ph t-Bu 2-CH₃, 3-Et—Ph 3-CH₃, 5-CH₃—Ph t-Bu 3-CH₂CH₂O-4-Ph 3-CH₃, 5-CH₃—Ph t-Bu 2-CH₃, 3-OMe—Ph 3,5-di-Cl-4-F—Ph t-Bu 2-CH₃, 3,4-OCH₂O—Ph 4-F—Ph t-Bu 2-Et, 3,4-OCH₂O—Ph 2-OCH₃—Ph t-Bu 3,4-di-Et—Ph 3-CH₃, 5-CH₃—Ph t-Bu 2-Et, 3-OMe—Ph 4-F—Ph t-Bu 2-Et, 3-OMe—Ph 2-OCH₃—Ph t-Bu 2-CH₃, 3-OMe—Ph 2-OCH₃-4-F—Ph t-Bu 2-Et, 3-OCH₃—Ph 2-Cl-6-CH₃-4-pyridyl t-Bu 2-Et, 3-OMe—Ph 3-OMe, 5-OMe—Ph t-Bu 2-I, 3-OMe—Ph 3-CH₃, 5-OMe—Ph t-Bu 3,4-ethylenedioxy-Ph 2-OCH₃—Ph t-Bu 3,4-(CH₂)₄—Ph 3-CH₃, 5-CH₃—Ph t-Bu 2-Et, 3-OMe—Ph 2,3-OCH₂O—Ph t-Bu 2-F, 4-Et—Ph 4-F—Ph t-Bu 2-Et, 3-OMe—Ph 3,4-methylenedioxy-Ph t-Bu 2-CH₃, 3,4-ethylenedioxy-Ph 4-F—Ph t-Bu 3,4-OCH(CH₃)O—Ph 3-CH₃, 5-CH₃—Ph t-Bu 2-Et, 3,4-OCH(CH₃)O—Ph 3-CH₃, 5-CH₃—Ph t-Bu 2-CH₃, 3,4-ethylenedioxy-Ph 3-OCH₃—Ph t-Bu 3-OCH(CH₃)CH₂O-4-Ph 3-CH₃, 5-CH₃—Ph t-Bu 2-Br, 3,4-ethylenedioxy-Ph 3-CH₃, 5-CH₃—Ph t-Bu 2-Et, 3,4-ethylenedioxy-Ph 3-CH₃, 5-Cl—Ph t-Bu 2-Et, 3,4-ethylenedioxy-Ph 3-CH₃—Ph t-Bu 2-Et, 3,4-ethylenedioxy-Ph 2-OCH₃—Ph t-Bu 2-Et, 3,4-ethylenedioxy-Ph 3-OCH₃—Ph t-Bu 3-S—C═N-4-Ph 3-CH₃, 5-CH₃—Ph t-Bu 2-Et, 3-OMe—Ph 2-OCH₃-4-Cl—Ph t-Bu 2-Et, 3-OMe—Ph 2,5-di-OCH₃—Ph t-Bu 2-CH₃, 4,5-methylenedioxy-Ph 3-CH₃, 5-CH₃—Ph t-Bu 3-CH₂OCH₂O-4-Ph 3-CH₃, 5-CH₃—Ph t-Bu 2-CH₃, 3-OCH₂OCH₂-4-Ph 2-OCH₃—Ph t-Bu 2-Et, 3-OCH₂OCH₂-4-Ph 4-F—Ph t-Bu 2-Cl 4,5-methylenedioxy-Ph 3-CH₃, 5-CH₃—Ph t-Bu 2,3,6-tri-F—Ph 2-Cl-4-F—Ph t-Bu 2-Et, 3-OMe—Ph 2,6-F—Ph t-Bu 2-Et, 3-OMe—Ph 3-F—Ph t-Bu 2-Et, 3-OMe—Ph 3-Br—Ph t-Bu 2-Et, 3-OMe—Ph 2-NO₂—Ph t-Bu 2-Et, 3-OMe—Ph 2,3-F—Ph t-Bu 2-Et, 3-OMe—Ph 3,4,5-tri-OCH₃—Ph t-Bu 2-Et, 3-OMe—Ph 3-CF₃, 5-F—Ph t-Bu 2-Et, 3-OMe—Ph 3-CN—Ph t-Bu 2-Vinyl, 3-OMe—Ph 2,4-di-Cl-5-F—Ph t-Bu 2-Et, 3-OCH₂OCH₂-4-Ph Ph t-Bu 2-Et, 3-OMe—Ph 3-CH₃, 5-CH₃—Ph —C(CH₃)₂C(O)OEt 2-Et, 3-OMe—Ph 3-CH₃, 5-CH₃—Ph —C(CH₃)₂CH₂OH 2-Et, 3-OMe—Ph 3-CH₃, 5-CH₃—Ph —C(CH₃)₂CHO 2-Et, 3-OMe—Ph 3-CH₃, 5-CH₃—Ph —C(CH₃)₂CH₂OCH₃ 2-Et, 3-OMe—Ph 3-CH₃, 5-CH₃—Ph —C(CH₃)₂CH═NOH 2-NH₂, 3-OMe—Ph 3-CH₃, 5-CH₃—Ph t-Bu 2-Et, 3-OMe—Ph 3-CH₂OAc, 5-CH₃—Ph t-Bu 2-Et, 3-OMe—Ph 3-CH₃, 5-CH₃—Ph —C(CH₃)₂CH₂OC(O)CH₃ 2-CH₃, 3-OH—Ph 2,3,4-F—Ph t-Bu 2-CH₃, 3-OH—Ph 3-Cl-5-OCH₃-4-pyridyl t-Bu 2-CH₃, 3-OH—Ph 2,6-di-Cl-4-pyridyl t-Bu 2-CH₃, 3-OH—Ph 3-OCH₃-4-pyridyl t-Bu 2-CH₃, 3-OH—Ph 3,5-di-OCH₃-4-CH₃—Ph t-Bu 2-CH₃, 3-CH₂CH₂CH₂O-4-Ph 2-OCH₃—Ph t-Bu 2-Et, 3-OMe—Ph 2,4-di-Cl-5-F—Ph t-Bu 2-CH₃, 3-CH₂CH₂CH₂O-4-Ph 2,4-di-Cl-5-F—Ph t-Bu 2-CH₃, 3-CH₂CH₂CH₂O-4-Ph 2-F, 5-CH₂—Ph t-Bu 2-CH₃, 3-CH₂CH₂CH₂O-4-Ph 3,5-di-OCH₃-4-CH₃—Ph t-Bu 2-Et, 3,4-ethylenedioxy-Ph 2,5-F—Ph t-Bu 2-Et, 3,4-ethylenedioxy-Ph 2,3,4-F—Ph t-Bu 2-Et, 3,4-ethylenedioxy-Ph 2,3,4,5--Ph t-Bu 2-Et, 3,4-ethylenedioxy-Ph 3-CF₃-4-F—Ph t-Bu 2-Et, 3,4-ethylenedioxy-Ph 2,6-di-Cl-4-pyridyl t-Bu 2-Et, 3,4-ethylenedioxy-Ph 2-OCH₃—Ph t-Bu 2-Et, 3,4-ethylenedioxy-Ph 2,4-di-Cl-5-F—Ph t-Bu 2-Et, 3,4-ethylenedioxy-Ph 2-F, 4-Cl—Ph t-Bu 2-CH₃, 3-OAc—Ph 3,5-di-OCH₃4-CH₃—Ph t-Bu 2-Et, 3-OMe—Ph 2-OCH₃-5-Cl—Ph t-Bu 2-Et, 3,4-OCH₂O—Ph 2-OCH₃-4-Cl—Ph t-Bu 2-CH₃, 3-CH₂CH₂CH₂O-4-Ph 2-OCH₃-5-Cl—Ph t-Bu 2-Et, 3-OMe—Ph 2-NO₂-5-CH₃—Ph t-Bu 2-Et, 3-OMe—Ph 2-NO₂-4-Cl—Ph t-Bu 2-Et, 3-OMe—Ph 2-NO₂-5-Cl—Ph t-Bu 2-CH₃, 3-CH₂CH₂CH₂O-4-Ph 2-NO₂-5-CH₃—Ph t-Bu Benzo[1,2,5]oxadiazole-5-yl 2-OCH₃-4-Cl—Ph t-Bu 2-Vinyl, 3-OMe—Ph 2-Cl, 5-NO₂—Ph t-Bu 2-Vinyl, 3-OMe—Ph 2-OCH₃-4-Cl—Ph t-Bu 2-Et, 3-OCH₃—Ph 1-methyl-1H-indole-2-yl t-Bu 2-Et, 3,4-ethylenedioxy-Ph 3,5-di-OCH₃-4-CH₃—Ph t-Bu 2-Cl, 3-CH₂OCH₂O-4-Ph 3-CH₃, 5-CH₃—Ph t-Bu 2-F, 4-Et—Ph 3-NO₂—Ph t-Bu 2-F, 4-Et—Ph 3-OCH₃—Ph t-Bu 2-Cl, 3-CH₂OCH₂O-4-Ph 3,5-di-OCH₃-4-CH₃—Ph t-Bu 2-F, 4-Et—Ph 2,6-di-Cl-4-pyridyl t-Bu 2-F, 4-Et—Ph 3,5-di-OCH₃-4-CH₃—Ph t-Bu 2-F, 4-Et—Ph 3,4,5-F—Ph t-Bu 2-F, 4-Et—Ph 3-CH₃—Ph t-Bu 2-F, 4-Et—Ph 2-OCH₃—Ph t-Bu 2-F, 4-Et—Ph 2-NO₂-5-F—Ph t-Bu 2-F, 4-Et—Ph 2-OCH₂CF₃, 5-OCH₃—Ph t-Bu 2-F, 4-Et—Ph 2-Cl-6-CH₃-4-pyridyl t-Bu 2-F, 4-Et—Ph 2,6-di-OCH₃-3-pyridyl t-Bu 3-NH—C═C-4-Ph 3-CH₃, 5-CH₃—Ph t-Bu 2-Et, 3-OMe—Ph 2-S(O)CH₃—Ph t-Bu 3,4-OCF₂O—Ph 2-NO₂—Ph t-Bu 3,4-OCF₂O—Ph 3-CH₃, 5-CH₃—Ph t-Bu 3,4-OCF₂O—Ph 3-OCH₃—Ph t-Bu 2-Et, 3-OMe—Ph 3-Br—Ph —C(CH₃)₂CN 2-CH₂OMe, 3-OMe—Ph 3,5-di-Cl—Ph t-Bu 2-Et, 3-OMe—Ph 3-CH═NOH, 5-CH₃—Ph t-Bu 2-Et, 3-OMe—Ph 3-CH═NNHCONH₂, 5-CH₃—Ph t-Bu 2-Et, 3-OMe—Ph 3-CH═NNHCOCONH₂, 5-CH₃—Ph t-Bu 2-Et, 3-OMe—Ph 3-CH₃, 5-CH₃—Ph —C(CH₃)₂CN 2-Et, 3-OMe—Ph 3,5-di-OCH₃-4-CH₃—Ph —C(CH₃)₂CN 2-Et, 3-OCH₂OCH₂-4-Ph 2-OCH₃—Ph t-Bu 2-CH₃, 3-CH₂CH₂CH₂O-4-Ph 2,4,5-F—Ph t-Bu 2-CH₃, 3-CH₂CH₂CH₂O-4-Ph 3,4,5-F—Ph t-Bu 2-CH₃, 3-CH₂CH₂CH₂O-4-Ph 3-F—Ph t-Bu 2-Et, 3,4-OCH₂O—Ph 3-CF₃—Ph t-Bu 2-CH₃, 3-CH₂CH₂CH₂O-4-Ph 4-F—Ph t-Bu 2-CH₃, 3-CH₂CH₂CH₂O-4-Ph 3,4-F—Ph t-Bu 2-CH₃, 3-CH₂CH₂CH₂O-4-Ph 3,5-di-F—Ph t-Bu 2-CH₃, 3-CH₂CH₂CH₂O-4-Ph 2,3,4,5-tetra-F—Ph t-Bu 2-Et, 3-OCH₂OCH₂-4-Ph 4-CH₃—Ph t-Bu 2-Et, 3-OMe—Ph 3,5-di-OCH₃-4-OAc—Ph t-Bu 2-Et, 3-OMe—Ph 3,5-di-OCH₃-OH—Ph t-Bu 2-CH₃, 3,4-ethylenedioxy-Ph 3,5-di-OCH₃-4-CH₃—Ph t-Bu 2-CH₃, 3,4-ethylenedioxy-Ph 2,6-di-OCH₃-3-pyridyl t-Bu 2-CH₃, 3,4-ethylenedioxy-Ph 2,6-di-Cl-4-pyridyl t-Bu 2-CH₃, 3,4-ethylenedioxy-Ph 3-F—Ph t-Bu 2-CH₃, 3,4-ethylenedioxy-Ph 3-CF₃, 5-F—Ph t-Bu 2-CH₃, 3,4-ethylenedioxy-Ph 2-NO₂-5-CH₃—Ph t-Bu 2-ethyl, 3-methoxy 4,6-dimethyl-pyridyl t-Bu 2-CH₃, 3,4-ethylenedioxy-Ph 3,5-di-CH₃—Ph —CH(Et)C(CH₃)₃ 2-CH₃, 3,4-ethylenedioxy-Ph 3,5-di-OCH₃-4-CH₃—Ph —CH(Et)C(CH₃)₃ 2-CH₃, 3,4-ethylenedioxy-Ph 3,5-di-CH₃—Ph —CH(n-Pr)C(CH₃)₃ 2-CH₃, 3,4-ethylenedioxy-Ph 3,5-di-OCH₃-4-CH₃—Ph —CH(n-Pr)C(CH₃)₃ 2-CH₂CH₃, 3,4-ethylenedioxy-Ph 3,5-di-CH₃—Ph —CH(Et)C(CH₃)₃ 2-CH₂CH₃, 3,4-ethylenedioxy-Ph 3,5-di-OCH3-4-CH3—Ph —CH(Et)C(CH₃)₃ 2-CH₂CH₃, 3,4-ethylenedioxy-Ph 3,5-di-CH₃—Ph —CH(n-Pr)C(CH₃)₃ 2-CH₂CH₃, 3,4-ethylenedioxy-Ph 3,5-di-OCH₃-4-CH₃—Ph —CH(n-Pr)C(CH₃)₃ 2-CH₃, 3-OCH₃—Ph 2-methoxy-6-trifluoromethyl-3- —C(CH₃)₃ pyridyl 2-CH₃, 3-OCH₃—Ph 1-methyl-2-oxo-6-trifluoromethyl- —C(CH₃)₃ 3-pyridyl 2-CH₃, 3-OCH₃—Ph 2,6-dimethoxy-4-pyrimidinyl —C(CH₃)₃ 2-CH₃, 3-OCH₃—Ph 3,6-dimethoxy-4-pyridazinyl —C(CH₃)₃ 2-CH₃, 3-OCH₃—Ph 3,6-dichloro-4-pyridazinyl —C(CH₃)₃ 2-CH₃, 3-OCH₃—Ph 4-pyridazinyl —C(CH₃)₃ 2-CH₃, 3-OCH₃—Ph 3-oxo-6-methoxy-4-pyridazinyl —C(CH₃)₃ 2-CH₃, 3-OCH₃—Ph 3,5-di-CH₃—Ph —CH(Et)C(CH₃)₃ 2-CH₃, 3-OCH₃—Ph 3,5-di-OCH₃-4-CH₃—Ph —CH(Et)C(CH₃)₃ 2-CH₃, 3-OCH₃—Ph 3,5-di-CH₃—Ph —CH(n-Pr)C(CH₃)₃ 2-CH₃, 3-OCH₃—Ph 3,5-di-OCH₃-4-CH₃—Ph —CH(n-Pr)C(CH₃)₃ 2-CH₂CH₃, 3-OCH₃—Ph 3,5-di-CH₃—Ph —CH(Et)C(CH₃)₃ 2-CH₂CH₃, 3-OCH₃—Ph 3,5-di-OCH₃-4-CH₃—Ph —CH(Et)C(CH₃)₃ 2-CH₂CH₃, 3-OCH₃—Ph 3,5-di-CH₃—Ph —CH(n-Pr)C(CH₃)₃ 2-CH₂CH₃, 3-OCH₃—Ph 3,5-di-OCH₃-4-CH₃—Ph —CH(n-Pr)C(CH₃)₃ 2-CH₃, 3-OCH₃—Ph 3,5-di-CH₃—Ph —CH(Et)C(CH₃)₃ 2-CH₃, 3-OH—Ph 3-OCH₃-4-pyridyl —C(CH₃)₃ 4-CH(OH)CH₃—Ph 3,5-di(CH₂OH)—Ph —C(CH₃)₃ 2-CH₂CH₃, 3-OCH₃—Ph 2-S(O)CH₃—Ph —C(CH₃)₃ 4-C(O)CH₃—Ph 3,5-di-CO₂H—Ph —C(CH₃)₃ 2-CH₃, 3,4-ethylenedioxy-Ph 2,6-di-OCH₃-3-pyridyl —C(CH₃)₃ 2-CH₂CH₃, 3,4-ethylenedioxy-Ph 3-CF₃-4-F-phenyl —C(CH₃)₃ 2-F, 4-CH₂CH₃—Ph 3,5-di-CH₃—Ph —C(CH₃)₃ 2-CH₂CH₃, 3-OCH₃—Ph 2-SO₃H—Ph —C(CH₃)₃ 2-CH₃, 3-CH₂CH₂CH₂O-4-Ph 3,5-di-CH₃—Ph —C(CH₃)₃ 4-CH₂CH₃—Ph 3,5-di-CH₃—Ph —CH(CH₃)C(CH₃)₃ 2-CH₂CH₃, 3,4-ethylenedioxy-Ph 3-CH₃—Ph —C(CH₃)₃ 2,3-di-CH₃—Ph Ph —CH(Et)(n-Bu) 2,3-di-CH₃—Ph 3-CH₃—Ph —CH(Et)(t-Bu) 2-CH₃, 3,4-ethylenedioxy-Ph 3,5-di-OCH₃, 4-OH—Ph —C(CH₃)₃ 2-F, 3-CH₂OCH₂O-4-Ph 3,5-di-CH₃—Ph —C(CH₃)₃ 2-CH₃, 3,4-ethylenedioxy-Ph 2-S(O)CH₃—Ph —C(CH₃)₃ 2-CH₃, 3,4-ethylenedioxy-Ph 3,5-di-OCH₃, 4-CH₃—Ph —C(CH₃)₂CN 2-CH₂CH₃-3-OCH-3-Ph 6-CH₃-2-pyridyl- —C(CH₃)₃ 2-CH₃, 3,4-ethylenedioxy-Ph 2-NO₂-3,5-di-OCH₃, 4-CH₃—Ph —C(CH₃)₃ 2-CH₃, 3,4-ethylenedioxy-Ph 3,5-di-CH₃—Ph —C(CH₃)₃ 4-CH₂CH₃—Ph 3,5-di-CH₃—Ph —C(CH₃)₃ 2-CH₃-3-OCH₃—Ph 3,5-di-CH₃—Ph —C(CH₃)₃ 4-CH₂CH₃—Ph 3,5-di-CH₃—Ph —CH(Et)(t-Bu) 4-CH₂CH₃—Ph 2-OCH₃-3-pyridyl —CH(Et)(t-Bu) 4-CH₂CH₃—Ph 3,5-di-CH₃—Ph —CH(n-Bu)(t-Bu) 4-CH₂CH₃—Ph 3,5-di-OCH₃, 4-CH₃—Ph —CH(n-Bu)(t-Bu) 4-CH₂CH₃—Ph 2-OCH₃-3-pyridyl —CH(n-Bu)(t-Bu) 4-CH₂CH₃—Ph 3,5-di-CH₃—Ph —CH(Ph)(t-Bu) 4-CH₂CH₃—Ph 3,5-di-OCH₃, 4-CH₃—Ph —CH(Ph)(t-Bu) 4-CH₂CH₃—Ph 2-OCH₃-3-pyridyl —CH(Ph)(t-Bu) 2-CH₂CH₃, 3-OCH₃—Ph 5-benzimidazolyl —C(CH₃)₃ 2-CH₂CH₃, 3-OCH₃—Ph 1-(or 3-)trityl-5-benzimidazolyl —C(CH₃)₃ 2-CH₂CH₃, 3-OCH₃—Ph 5-methyl-1-phenyl-1H-pyrazole-3- —C(CH₃)₃ yl 2-CH₂CH₃, 3-OCH₃—Ph 3-chloro-6-methylsulfanyl- —C(CH₃)₃ pyrazine-2-yl 2-CH₂CH₃, 3-OCH₃—Ph 1H-indazole-3-yl —C(CH₃)₃ 2-CH₂CH₃, 3-OCH₃—Ph 1-trityl-1H-indazole-3-yl —C(CH₃)₃ 2-CH₂CH₃, 3-OCH₃—Ph 5-methoxycarbonyl-2-pyridyl —C(CH₃)₃ 2-CH₂CH₃, 3-OCH₃—Ph pyrazine-2-yl —C(CH₃)₃ 2-CH₂CH₃, 3-OCH₃—Ph 3,5-di-CH₃—Ph —C(CH₃)₂CH₂OSi(CH₃)2tBu 2-CH₂CH₃, 3-OCH₃—Ph 3,5-di-CH₃—Ph —C(CH₃)₂CH═NCH₂CH₂OH 2-CH₂CH₃, 3-OCH₃—Ph 3,5-di-CH₃—Ph —C(CH₃)₂CH═NNHC(O)NH₂ 2-CH₂CH₃, 3-OCH₃—Ph 3,5-di-CH₃—Ph —C(CH₃)₂CH═NNHC(O)C(O)NH₂ 2-CH₂CH₃, 3-OCH₃—Ph 3,5-di-CH₃—Ph —C(CH₃)₂COOH 2-CH₂S(O)CH₃, 3-OCH₃—Ph 3,5-di-CH₃—Ph —C(CH₃)₃ 2-CH₂S(O)₂CH₃, 3-OCH3—Ph 3,5-di-CH₃—Ph —C(CH₃)₃ 2-CH₂NMe₂, 3-OCH₃—Ph 3,5-di-CH₃—Ph —C(CH₃)₃ 2-CH₂NHCH₃, 3-OCH₃—Ph 3,5-di-CH₃—Ph —C(CH₃)₃ 2-CH═CH₂, 3-OCH₃—Ph— 3,5-di-CH₃—Ph —C(CH₃)₃ 2-CH₂OMe, 3-OCH₃—Ph— 3,5-di-CH₃—Ph —C(CH₃)₃ 2-CH₂SCH₃, 3-OCH₃—Ph 3,5-di-CH₃—Ph —C(CH₃)₃ 2-CH₂OCH₂CH═CH₂, 3-OCH₃—Ph 3,5-di-CH₃—Ph —C(CH₃)₃ 2-CH₂Cl, 3-OCH₃—Ph— 3,5-di-CH₃—Ph —C(CH₃)₃ 2-CH₂OH, 3-OCH₃—Ph— 3,5-di-CH₃—Ph —C(CH₃)₃ 2-CH₂OAc, 3-OCH₃—Ph 3,5-di-CH₃—Ph —C(CH₃)₃ 2-CH₂F, 3-OCH₃—Ph— 3,5-di-CH₃—Ph —C(CH₃)₃ 2-CH₃, 3-OCH₃ 3,5-di-CH₃ —CH(n-Bu)(t-Bu) 2-CH₃, 3-OCH₃ 3,5-di-OCH₃, 4-CH₃ —CH(n-Bu)(t-Bu) 2-CH₂CH₃, 3-OCH—Ph 5-Methyl-pyrazine-2-yl- —C(CH₃)₃

In another embodiment, the activating ligand is a compound having Formula I selected from the group consisting of:

-   3,5-Dimethyl-benzoic acid     N-tert-butyl-N′-(3-hydroxymethyl-5-methyl-2,3-dihydro-benzo[1,4]dioxine-6-carbonyl)-hydrazide; -   3,5-Dimethyl-benzoic acid     N-tert-butyl-N′-[3-(tert-butyl-dimethyl-silanyloxymethyl)-5-methyl-2,3-dihydro-benzo[1,4]dioxine-6-carbonyl]-hydrazide; -   7-[N′-tert-Butyl-N′-(3,5-dimethyl-benzoyl)-hydrazinocarbonyl]-8-methyl-2,3-dihydro-benzo[1,4]dioxine-2-carboxylic     acid; -   7-[N′-tert-Butyl-N′-(3,5-dimethyl-benzoyl)-hydrazinocarbonyl]-8-methyl-2,3-dihydro-benzo[1,4]dioxine-2-carboxylic     acid methyl ester, -   3,5-Dimethyl-benzoic acid     N-tert-butyl-N′-(3-semicarbazidomethyl-5-methyl-2,3-dihydro-benzo[1,4]dioxine-6-carbonyl)-hydrazide; -   Phenyl-carbamic acid     7-[N′-tert-butyl-N′-(3,5-dimethyl-benzoyl)-hydrazinocarbonyl]-8-methyl-2,3-dihydro-benzo[1,4]dioxin-2-ylmethyl     ester; -   3,5-Dimethyl-benzoic acid     N′-[3-(2-amino-ethyl)-5-methyl-2,3-dihydro-benzo[1,4]dioxine-6-carbonyl]-N-tert-butyl-hydrazide; -   7-[N′-tert-Butyl-N′-(3,5-dimethyl-benzoyl)-hydrazinocarbonyl]-8-methyl-2,3-dihydro-benzo[1,4]dioxine-2-carboxylic     acid pentafluorophenyl ester; -   7-[N′-tert-Butyl-N′-(3,5-dimethyl-benzoyl)-hydrazinocarbonyl]-8-methyl-2,3-dihydro-benzo[1,4]dioxine-2-carboxylic     acid methylamide; -   3,5-Dimethyl-benzoic acid     N-tert-butyl-N′-(3-formyl-5-methyl-2,3-dihydro-benzo[1,4]dioxine-6-carbonyl)-hydrazide; -   Toluene-4-sulfonic acid     7-[N′-tert-butyl-N′-(3,5-dimethyl-benzoyl)-hydrazinocarbonyl]-8-methyl-2,3-dihydro-benzo[1,4]dioxin-2-ylmethyl     ester; -   3,5-Dimethyl-benzoic acid     N-tert-butyl-N′-[3-(hydroxyimino-methyl)-5-methyl-2,3-dihydro-benzo[1,4]dioxine-6-carbonyl]-hydrazide; -   3,5-Dimethyl-benzoic acid     N-tert-butyl-N′-(3-cyanomethyl-5-methyl-2,3-dihydro-benzo[1,4]dioxine-6-carbonyl)-hydrazide; -   3,5-Dimethyl-benzoic acid     N-tert-butyl-N′-(5-methyl-3-methylsulfanylmethyl-2,3-dihydro-benzo[1,4]dioxine-6-carbonyl)-hydrazide; -   3,5-Dimethyl-benzoic acid     N-tert-butyl-N′-(3-methanesulfonylmethyl-5-methyl-2,3-dihydro-benzo[1,4]dioxine-6-carbonyl)-hydrazide; -   3,5-Dimethyl-benzoic acid     N-tert-butyl-N′-(3-fluoromethyl-5-methyl-2,3-dihydro-benzo[1,4]dioxine-6-carbonyl)-hydrazide; -   3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-heptyl)-N′-(3-methoxy-2-methyl-benzoyl)-hydrazide; -   3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-heptyl)-N′-(4-ethyl-benzoyl)-hydrazide; -   3,5-Dimethoxy-4-methyl-benzoic     acid-N-(1-tert-butyl-heptyl)-N′-(3-methoxy-2-methyl-benzoyl)-hydrazide; -   3,5-Dimethoxy-4-methyl-benzoic     acid-N-(1-tert-butyl-heptyl)-N′-(4-ethyl-benzoyl)-hydrazide; -   2-Methoxy-nicotinic acid     N-(1-tert-butyl-heptyl)-N′-(4-ethyl-benzoyl)-hydrazide; -   3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-3,4,4-trimethyl-pent-2-enyl)-N′-(3-methoxy-2-methyl-benzoyl)-hydrazide; -   3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-2-cyano-vinyl)-N′-(3-methoxy-2-methyl-benzoyl)-hydrazide; -   3,5-Dimethyl-benzoic acid     N-(1-butyl-2,2-dimethyl-pentyl)-N′-(3-methoxy-2-methyl-benzoyl)-hydrazide;     and -   3,5-Dimethyl-benzoic acid     N-(1-butyl-2,2-dimethyl-pent-4-enyl)-N′-(3-methoxy-2-methyl-benzoyl)-hydrazide.

In another embodiment, the activating ligand is an enantiomerically enriched compound having Formula II:

wherein:

-   -   A is alkoxy, arylalkyloxy, aryloxy, arylalkyl, optionally         substituted aryl or optionally substituted heteroaryl;     -   B is optionally substituted aryl or optionally substituted         heteroaryl; and     -   R¹ and R² are independently optionally substituted alkyl,         arylalkyl, hydroxyalkyl, haloalkyl, optionally substituted         cycloalkyl, optionally substituted alkenyl, optionally         substituted alkynyl, optionally substituted heterocycle,         optionally substituted aryl or optionally substituted         heteroaryl;     -   with the proviso that R¹ does not equal R²;     -   wherein the absolute configuration at the asymmetric carbon atom         bearing R¹ and R² is predominantly S.

In another embodiment, the activating ligand is an enantiomerically enriched compound having Formula III:

wherein:

-   -   A is alkoxy, arylalkyloxy, aryloxy, arylalkyl, optionally         substituted aryl or optionally substituted heteroaryl;     -   B is optionally substituted aryl or optionally substituted         heteroaryl; and     -   R¹ and R² are independently optionally substituted alkyl,         arylalkyl, hydroxyalkyl, haloalkyl, optionally substituted         cycloalkyl, optionally substituted alkenyl, optionally         substituted alkynyl, optionally substituted heterocycle,         optionally substituted aryl or optionally substituted         heteroaryl,     -   with the proviso that R¹ does not equal R²;     -   wherein the absolute configuration at the asymmetric carbon atom         bearing R¹ and R² is predominantly R.

In another embodiment, the activating ligand is an enantiomerically enriched compound having Formula III, wherein:

-   -   A is:

-   -   B is

-   -   R^(3a), R^(3b), R^(3c), R^(3d), R^(3e), R^(3f), R^(3g), R^(3h),         R^(3i) and R^(3j) are independently selected from hydrogen,         halo, (C₁-C₄)alkyl, or (C₁-C₄)alkoxy;     -   R¹ is (C₁-C₆)alkyl, hydroxy(C₁-C₄)alkyl, or (C₂-C₄)alkenyl; and     -   R² is optionally substituted (C₁-C₆)alkyl.

In another embodiment, the activating ligand is a compound having Formula III selected from the group consisting of:

-   (R)—N′-(1-tert-Butyl-butyl)-N′-(3,5-dimethyl-benzoyl)-hydrazinecarboxylic     acid benzyl ester; -   (R)—N′-(1-tert-Butyl-butyl)-N′-(3,5-dimethyl-benzoyl)-hydrazinecarboxylic     acid tert-butyl ester; -   (R)—N′-(1-tert-Butyl-4-hydroxy-butyl)-N′-(3,5-dimethyl-benzoyl)-hydrazine     carboxylic acid benzyl ester; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(2-ethyl-3-methoxy-benzoyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N′-benzoyl-N-(1-tert-butyl-butyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(2-methyl-benzoyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(2-methoxy-benzoyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(2-fluoro-benzoyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(2-chloro-benzoyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N′-(2-bromo-benzoyl)-N-(1-tert-butyl-butyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(3-methyl-benzoyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(3-methoxy-benzoyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(3-chloro-benzoyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(4-methyl-benzoyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(4-ethyl-benzoyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(4-methoxy-benzoyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(4-chloro-benzoyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(2,6-difluoro-benzoyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(2,6-dichloro-benzoyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(3,4-dimethoxy-benzoyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(3,5-difluoro-benzoyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(3,5-dimethoxy-4-methyl-benzoyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(4-methyl-benzo[1,3]dioxole-5-carbonyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(5-methyl-2,3-dihydro-benzo[1,4]dioxine-6-carbonyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(5-ethyl-2,3-dihydro-benzo[1,4]dioxine-6-carbonyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(naphthalene-1-carbonyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(naphthalene-2-carbonyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(thiophene-2-carbonyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(2,5-dimethyl-furan-3-carbonyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(2-chloro-pyridine-3-carbonyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(6-chloro-pyridine-3-carbonyl)-hydrazide; -   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(3-methoxy-2-methyl-benzoyl)-hydrazide; -   (R)-3,5-Dimethoxy-4-methyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(3-methoxy-2-methyl-benzoyl)-hydrazide;     and -   (R)-3,5-Dimethyl-benzoic acid     N′-(4-ethyl-benzoyl)-N-(1-phenethyl-but-3-enyl)-hydrazide.

In another embodiment, the activating ligand is a compound having Formula IV:

wherein:

-   -   Q is O or S;     -   R¹ is selected from the group consisting of hydrogen,         (C₁-C₁₂)alkyl, (C₃-C₁₂)cycloalkyl,         (C₃-C₁₂)cycloalkyl(C₁-C₃)alkyl, (C₁-C₁₂)haloalkyl,         (C₂-C₁₂)alkenyl, (C₃-C₁₂)cycloalkenyl, (C₂-C₁₂)haloalkenyl,         (C₂-C₁₂)alkynyl, (C₁-C₆)alkoxy(C₁-C₆)alkyl,         (C₁-C₆)alkylthio(C₁-C₆)alkyl, (C₁-C₆)alkoxycarbonyl,         succinimidylmethyl, benzosuccinimidylmethyl, optionally         substituted phenyl, optionally substituted 1-naphthyl,         optionally substituted 2-naphthyl, optionally substituted         phenyl(C₁-C₃)alkyl, optionally substituted phenyl(C₂-C₃)alkenyl,         optionally substituted naphthyl(C₁-C₃)alkyl, optionally         substituted phenoxy(C₁-C₃)alkyl, optionally substituted         phenylamino, and optionally substituted heterocycle;     -   R² and R³ are each independently selected from hydrogen,         (C₁-C₆)alkyl, and (C₁-C₆)haloalkyl;     -   R⁴ is hydrogen, (C₁-C₆)alkyl, or (C₁-C₆)haloalkyl;     -   R⁵ and R⁶ are each independently selected from the group         consisting of hydrogen, (C₁-C₁₂)alkyl, (C₃-C₁₂)cycloalkyl,         (C₁-C₁₂)haloalkyl, (C₂-C₁₂)alkenyl, (C₃-C₁₂)cycloalkenyl,         (C₂-C₁₂)haloalkenyl, (C₂-C₁₂)alkynyl, (C₁-C₆)alkoxy(C₁-C₆)alkyl,         (C₁-C₆)alkylthio(C₁-C₆)alkyl, aminocarbonyl, aminothiocarbonyl,         formyl, (C₁-C₆)alkylsulfinyl, (C₁-C₆)alkylsulfonyl,         (C₁-C₆)alkylcarbonyl, cyclo(C₃-C₆)alkylcarbonyl,         halo(C₁-C₆)alkylcarbonyl, (C₁-C₆)alkylaminocarbonyl,         di(C₁-C₆)alkylaminocarbonyl, (C₁-C₆)alkoxycarbonyl,         (C₁-C₆)alkoxycarbonylcarbonyl, or phenyl(C₂-C₃)alkenylcarbonyl,         optionally substituted phenyl, optionally substituted         1-naphthyl, optionally substituted 2-naphthyl, optionally         substituted phenyl(C₁-C₃)alkyl, optionally substituted         phenyl(C₂-C₃)alkenyl, optionally substituted phenylcarbonyl, or         optionally substituted heterocycle;     -   R⁷, R⁸, R⁹, and R¹⁰ are each independently selected from the         group consisting of hydrogen, cyano, nitro, halogen,         (C₁-C₁₂)alkyl, (C₃-C₁₂)cycloalkyl, (C₁-C₁₂)haloalkyl,         (C₂-C₁₂)alkenyl, (C₃-C₁₂)cycloalkenyl, (C₂-C₁₂)haloalkenyl,         (C₂-C₁₂)alkynyl, halo(C₂-C₆)alkynyl, hydroxy, (C₁-C₆)alkoxy,         halo(C₁-C₆)alkoxy, (C₂-C₆)alkenyloxy, halo(C₂-C₆)alkenyloxy,         (C₂-C₆)alkynyloxy, halo(C₂-C₆)alkynyloxy, aryloxy,         (C₁-C₆)alkoxy(C₁-C₆)alkyl, (C₁-C₆)alkylthio,         halo(C₁-C₆)alkylthio, (C₂-C₆)alkenylthio,         halo(C₂-C₆)alkenylthio, (C₂-C₆)alkynylthio,         halo(C₂-C₆)alkynylthio, (C₁-C₆)alkylsulfinyl,         halo(C₁-C₆)alkylsulfinyl, (C₁-C₆)alkylsulfonyl,         halo(C₁-C₆)alkylsulfonyl, (C₁-C₆)alkylamino,         di(C₁-C₆)alkylamino, (C₁-C₃)alkoxy(C₁-C₃)alkyl,         (C₁-C₆)alkylthio(C₁-C₆)alkyl, (C₁-C₃)alkylsulfinyl(C₁-C₃)alkyl,         (C₁-C₃)alkylsulfonyl(C₁-C₃)alkyl, (C₁-C₃)alkylamino(C₁-C₃)alkyl,         di(C₁-C₃)alkylamino(C₁-C₃)alkyl, (C₁-C₆)alkylcarbonyl,         (C₁-C₆)alkylaminocarbonyl, di(C₁-C₆)alkylaminocarbonyl, or         (C₁-C₆)alkoxycarbonyl, optionally substituted phenyl, optionally         substituted 1-naphthyl, optionally substituted 2-naphthyl,         optionally substituted phenyl(C₁-C₃)alkyl, optionally         substituted phenyl(C₂-C₃)alkenyl, or optionally substituted         heterocycle.

In another embodiment, the activating ligand is a compound having Formula IV wherein:

-   -   Q is O;     -   R¹ is selected from the group consisting of 4-fluorophenyl,         3-fluorophenyl, 4-fluoro-3-methylphenyl,         4-fluoro-3-(trifluoromethyl)phenyl, 4-fluoro-3-iodophenyl,         3-fluoro-4-iodophenyl, 3,4-di-fluorophenyl, 4-ethylphenyl,         3-fluoro-4-methylphenyl, 3-fluoro-4-ethylphenyl,         3-chloro-4-fluorophenyl, 3-fluoro-4-chlorophenyl,         2-methyl-3-methoxyphenyl, 2-ethyl-3-methoxyphenyl,         2-ethyl-3,4-ethylenedioxyphenyl, 3-nitrophenyl, 4-iodophenyl,         3-fluoro-4-trifluoromethylphenyl, 3-methylphenyl,         4-methylphenyl, 4-chlorophenyl, 3-trifluoromethylphenyl,         3-methoxyphenyl, 3-chloro-6-pyridyl, 2-chloro-4-pyridyl,         phenylamino, 3-chlorophenylamino, 3-methylphenylamino,         4-chlorophenylamino, and 4-methylphenylamino;     -   R² is hydrogen, methyl or CF₃;     -   R³ is hydrogen, methyl or CF₃;     -   R⁴ is hydrogen;     -   R⁵ is optionally substituted phenyl, wherein the substituents         are selected from the group consisting of cyano, nitro, halogen,         (C₁-C₃)alkyl, halo(C₁-C₃)alkyl, (C₁-C₃)alkoxy,         halo(C₁-C₃)alkoxy, (C₃)alkenyloxy, (C₃)alkynyloxy,         (C₁-C₃)alkylthio, halo(C₁-C₃)alkylthio, (C₁-C₃)alkylsulfinyl,         halo(C₁-C₃)alkylsulfinyl, (C₁-C₃)alkylsulfonyl,         halo(C₁-C₃)alkylsulfonyl, (C₁-C₃)alkoxy(C₁-C₃)alkyl,         (C₁-C₂)alkylthio(C₁-C₂)alkyl, and (C₁-C₃)alkoxycarbonyl;     -   R⁶ is selected from the group consisting of hydrogen, formyl,         (C₁-C₃)alkylcarbonyl, and cyclo(C₃-C₆)alkylcarbonyl; and     -   R⁷, R⁸, R⁹, R¹⁰ are independently selected from the group         consisting of hydrogen, cyano, nitro, chlorine, fluorine,         methyl, trifluoromethyl, difluoromethyl, methoxy,         trifluoromethoxy, difluoromethoxy, methylthio,         trifluoromethylthio, difluoromethylthio, methylsulfinyl,         trifluoromethylsulfinyl, difluoromethylsulfinyl, methylsulfonyl,         trifluoromethylsulfonyl, difluoromethylsulfonyl, methoxymethyl,         and methoxycarbonyl, or R⁷/R⁸, R⁸/R⁹, or R⁹/R¹⁰ form a 5- or         6-membered heterocyclic ring.

In another embodiment, the activating ligand is a compound having Formula IV wherein Q is O, R² is methyl, and R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, and R¹⁰ are defined according to Table 4.

TABLE 4 Ligand Components R³, R⁴, R⁷, R⁹, and R¹ R¹⁰ R⁵ R⁶ R⁸ Stereo.¹ n-Hexyl H Ph H H cis n-Heptyl H Ph H H cis n-Bu H Ph H H cis 3-CF₃-4-F—Ph H 4-F—Ph H F trans 3-CF₃-4-F—Ph H 4-F—Ph H F cis 3-Cl-4-F—Ph H 4-F—Ph H F trans 3-Cl-4-F—Ph H 4-F—Ph H F cis 4-F—Ph H 4-F—Ph H F trans 4-F—Ph H 4-F—Ph H F cis Ph H 4-F—Ph H F trans Ph H 4-F—Ph H F cis 3-F-4-Me—Ph H 4-F—Ph H F cis 3-Me-4-F—Ph H 4-F—Ph H F cis 3-F-4-Me—Ph H 4-F—Ph H F trans 3,4-di-F—Ph H Ph H H cis 3-F-4-Me—Ph H Ph H H cis 3-F-4-CF₃—Ph H Ph H H cis 3,4-di-F—Ph H Ph H H trans 3-F-4-Me—Ph H Ph H H trans 3-F-4-CF₃—Ph H Ph H H trans 3,4-di-F—Ph H 4-Me—Ph H Me cis 3-F-4-Me—Ph H 4-Me—Ph H Me cis 3-F-4-CF₃—Ph H 4-Me—Ph H Me cis 3,4-di-F—Ph H 4-F—Ph H F trans 3-F-4-CF₃—Ph H 4-F—Ph H F trans 3,4-di-F—Ph H 4-F—Ph H F cis 3-F-4-CF₃—Ph H 4-F—Ph H F cis 3-F-4-Me—Ph H 4-Me—Ph H Me trans 4-Cl—Ph H Ph H H trans 4-CH₃OC(O)—Ph H Ph H H trans 3,4-OCH₂O—Ph H Ph H H trans 4-Cl—Ph H 4-Me—Ph H Me trans 4-CH₃OC(O)—Ph H 4-Me—Ph H Me trans 3,4-OCH₂O—Ph H 4-Me—Ph H Me trans 4-Cl—Ph H 4-F—Ph H F trans 4-Et—Ph H 4-F—Ph H F trans 4-CH₃OC(O)—Ph H 4-F—Ph H F trans 3,4-OCH₂O—Ph H 4-F—Ph H F trans 4-Me—Ph H Ph H H 80:20 cis:trans 4-Me—Ph H 4-F—Ph H H 75:25 cis:trans 4-Me—Ph H 2-Cl—Ph H H 80:20 cis:trans 4-Me—Ph H 3-Cl—Ph H H 50:50 cis:trans 4-Me—Ph H 4-Cl—Ph H H 80:20 cis:trans 4-Me—Ph H 3-Me—Ph H H 60:40 cis:trans 4-Me—Ph H 4-Me—Ph H H 70:30 cis:trans 4-Me—Ph H 3-MeO—Ph H H 60:40 cis:trans 4-Me—Ph H 4-MeO—Ph H H 80:20 cis:trans 3-F-4-Me—Ph H, 4-F—Ph H H 60:40 (R⁹ = Cl) cis:trans 3-F-4-CF₃—Ph H 4-Me—Ph H Me trans 2-Me-3-MeO—Ph H Ph H H cis 2-F—Ph H 4-Me—Ph H Me cis 2-Me—Ph H 4-Me—Ph H Me cis 2-MeO—Ph H 4-Me—Ph H Me cis 2-Me-3-MeO—Ph H 4-Me—Ph H Me cis 2-F—Ph H 4-F—Ph H F cis 2-Me—Ph H 4-F—Ph H F cis 2-MeO—Ph H 4-F—Ph H F cis 2-Me-3-MeO—Ph H 4-F—Ph H F cis 4-Et—Ph H Ph H H trans 4-Et—Ph H 4-Me—Ph H Me trans 4-Cl—Ph H Ph H H cis 4-Et—Ph H Ph H H cis 4-Cl—Ph H 4-Me—Ph H Me cis 4-Et—Ph H 4-Me—Ph H Me cis 4-Cl—Ph H 4-F—Ph H F cis 4-Et—Ph H 4-F—Ph H F cis Ph H Ph H H cis 3-F—Ph H Ph H H cis 2-CF₃—Ph H Ph H H cis 3-CF₃—Ph H Ph H H cis 4-CF₃—Ph H Ph H H cis Ph H 4-Me—Ph H Me cis 3-F—Ph H 4-Me—Ph H Me cis 2-CF₃—Ph H 4-Me—Ph H Me cis 3-CF₃—Ph H 4-Me—Ph H Me cis 4-CF₃—Ph H 4-Me—Ph H Me cis 3-F—Ph H 4-F—Ph H F cis 2-CF₃—Ph H 4-F—Ph H F cis 3-CF₃—Ph H 4-F—Ph H F cis 4-CF₃—Ph H 4-F—Ph H F cis 3-MeO—Ph H Ph H H cis 4-Me—Ph H Ph H H cis 4-MeO—Ph H Ph H H cis 4-CH₃OC(O)—Ph H Ph H H cis 3-Me—Ph H 4-Me—Ph H Me cis 3-MeO—Ph H 4-Me—Ph H Me cis 4-Me—Ph H 4-Me—Ph H Me cis 4-MeO—Ph H 4-Me—Ph H Me cis 4-CH₃OC(O)—Ph H 4-Me—Ph H Me cis 3-Me—Ph H 4-F—Ph H F cis 3-MeO—Ph H 4-F—Ph H F cis 4-Me—Ph H 4-F—Ph H F cis 4-MeO—Ph H 4-F—Ph H F cis 4-CH₃OC(O)—Ph H 4-F—Ph H F cis 4-MeO—Ph H Ph H H trans 4-Me—Ph H Ph H H trans Ph H Ph H H trans 4-MeO—Ph H 4-Me—Ph H Me trans 4-Me—Ph H 4-Me—Ph H Me trans Ph H 4-Me—Ph H Me trans 4-MeO—Ph H 4-F—Ph H F trans 4-Me—Ph H 4-F—Ph H F trans 6-Cl-3-pyridyl H Ph H H cis 5-isoxazolyl H Ph H H cis 3-F-4-Cl—Ph H Ph H H cis 2-Cl-4-pyridyl H Ph H H cis 2-Et-3-MeO—Ph H Ph H H cis 3-Cl-6-pyridyl H 4-Me—Ph H Me cis 5-isoxazolyl H 4-Me—Ph H Me cis 3-F-4-Cl—Ph H 4-Me—Ph H Me cis 2-Cl-4-pyridyl H 4-Me—Ph H Me cis 2-Et-3-MeO—Ph H 4-Me—Ph H Me cis 3-Cl-6-pyridyl H 4-F—Ph H F cis 5-isoxazolyl H 4-F—Ph H F cis 3-F-4-Cl—Ph H 4-F—Ph H F cis 2-Cl-4-pyridyl H 4-F—Ph H F cis 2-Et-3-MeO—Ph H 4-F—Ph H F cis 2-Thienyl H Ph Ac H Styryl H Ph Ac H 4-Cl—Ph H Ph 4-MeO—Ph—C(O) H furan-2-ylvinyl H Ph H H 2-Thienyl H Ph H H 4-t-butyl-Ph H Ph Ac H 4-F—Ph H 4-Me—Ph H Me Benzosuccinimidyl- H 4-Me—Ph H Me methyl n-Pr H 4-F—Ph benzoyl H n-Octyl H Ph H H cis Me H Ph 4-F—Ph—C(O) H 2-Cl—PhOCH₂ H Ph H H Benzyl H Ph H H 4-MeO—Ph H Ph 2-thiophenyl- H C(O) Me H Ph 4-Me—Ph—C(O) H 3-MeO—Ph H Ph n-hexanoyl H 4-t-butyl-Ph H Ph H H cis 4-MeO—Ph H, 2-Me—Ph H H (R¹⁰ = Me) 3-F—Ph H Ph 3-F—Ph(CO) H Ph H 3-MeO—Ph H H 4-n-pentyl-Ph H Ph H H 2-furanyl H Ph H H Ph H 3-MeO—Ph Ac H 4-Me—Ph H Ph 3-MeO—PhC(O) H Me H Ph 3-MeO—PhC(O) H 4-Me—Ph H Ph 4-F—Ph—C(O) H 4-Cl—Ph H 4-Me—Ph H Me CO₂Et H Ph EtOC(O)C(O) H 3,4-di-MeO-styryl H Ph H H cis Styryl H Ph styryl-C(O) H 3-Br—Ph H Ph H H Ph H 4-Me—Ph Ac H 4-MeO-styryl H Ph Ac H Benzosuccinimidyl- H Ph H H methyl 4-MeO—Ph H 4-Me—Ph H Me trans 4-MeO—Ph H Ph 4-MeO—Ph—C(O) H 3-NO₂—Ph H 4-Me—Ph H Me cyclopropyl H Ph cyclopropyl- H C(O) Me H 3-MeO—Ph benzoyl H 4--n-propyl H, 2-Me—Ph H H (R¹⁰ = Me) 3-NO₂—Ph H Ph H H cis 4-F—PhOCH₂ H Ph H H n-Pr H Ph 3-MeO—PhC(O) H 4-Cl—Ph H Ph 4-Me—Ph—C(O) H 4-Et—Ph H, 2-Me—Ph styryl-C(O) H (R¹⁰ = Me) Styryl H Ph H H cis 3-Me—Ph H Ph 3-Me—Ph—C(O) H 3,4-di-Cl—Ph H Ph H H cis 3-OH—Ph H Ph 3-Br—Ph(CO) H succinimidylmethyl H Ph H H 4-I—Ph H Ph H H cis 1-naphthylmethyl H Ph H H cyclohexylethyl H Ph H H CO₂Et H Ph H H 4-F—Ph H Ph 4-F—Ph—C(O) H 4-n-propyl-Ph H Ph H H 3-F—Ph H 4-Me—Ph H Me trans 4-CH₃S(O₂)NH—Ph H Ph H H NHPh H Ph H H 4-MeO-styryl H Ph H H cis i-Pr H 4-NO₂—Ph benzoyl H 3-Cl-benzofuran-2-yl H Ph 3-Cl- H benzothiophen- 2-yl 4-Cl—PhOCH₂ H Ph H H 4-MeO—Ph H Ph 4-MeO-styryl H CF₃ H Ph CF₃C(O) H Et H Ph 4-NO₂—Ph—C(O) H Ph H, 2-Me—Ph H H cis (R¹⁰ = Me) Me H Ph 2-F—Ph—C(O) H n-pentyl H Ph 2-F—Ph—C(O) H 4-Me—Ph H, 2-Me—Ph H H cis (R¹⁰ = Me) 3-F-4-Me—Ph H 4-Me—Ph 3-F-4-Me—Ph(CO) Me trans 3-F-4-CF₃—Ph H 4-Me—Ph 3-F-4-CF₃—Ph—C(O) Me trans 4-Cl—Ph H Ph 4-Cl—Ph—C(O) H trans 4-Et—Ph H Ph 4-Et—Ph—C(O) H trans 4-Cl—Ph H 4-Me—Ph 4-Cl—Ph—C(O) Me trans 4-Et—Ph H 4-Me—Ph 4-Et—Ph—C(O) Me trans 3,4-OCH₂O—Ph H 4-Me—Ph 3,4-OCH₂O—Ph—C(O) Me trans 3-F-4-Me—Ph H 4-F—Ph Ac F trans 3-F-4-Me—Ph H 4-F—Ph 3-F-4-Me—Ph(CO) F trans 3-F-4-Me—Ph H 4-F—Ph 3-F-4-Me—Ph(CO) F cis 3-Me—Ph H Ph H H trans 3-F—Ph H Ph H H trans 3-MeO—Ph H Ph H H trans 3-CF₃—Ph H Ph H H trans 3-Me—Ph H 4-Me—Ph H Me trans 3-F—Ph H 4-Me—Ph H Me trans 3-MeO—Ph H 4-Me—Ph H Me trans 3-CF₃—Ph H 4-Me—Ph H Me trans 3-Me—Ph H 4-F—Ph H F trans 3-F—Ph H 4-F—Ph H F trans 3-MeO—Ph H 4-F—Ph H F trans 3-CF₃—Ph H 4-F—Ph H F trans NHEt H Ph H H cis NHPh H Ph H H cis 4-Cl—Ph—NH H Ph H H cis 3-Cl—Ph—NH H Ph H H cis 4-Me—Ph—NH H Ph H H cis 3-Me—Ph—NH H Ph H H cis NHPh H 4-Me—Ph H Me cis 4-Cl—Ph—NH H 4-Me—Ph H Me cis 3-Cl—Ph—NH H 4-Me—Ph H Me cis 4-Me—Ph—NH H 4-Me—Ph H Me cis 3-Me—Ph—NH H 4-Me—Ph H Me cis NHPh H 4-F—Ph H F cis 4-Cl—Ph—NH H 4-F—Ph H F cis 3-Cl—Ph—NH H 4-F—Ph H F cis 4-Me—Ph—NH H 4-F—Ph H F cis 3-Me—Ph—NH H 4-F—Ph H F cis ¹Relative stereochemistry at 2- and 4-positions

In another embodiment, the activating ligand is a compound having Formula V, VI, or VII:

-   -   wherein         -   Q¹ and Q² are independently selected from the group             consisting of O and S,         -   n=1 or 2;         -   R¹ is selected from the group consisting of (C₁-C₆)alkyl,             (C₃-C₆)cycloalkyl, (C₁-C₆)haloalkyl, (C₃-C₆)halocycloalkyl,             (C₂-C₆)alkenyl, (C₂-C₆)haloalkenyl, (C₂-C₆)alkynyl,             (C₂-C₆)haloalkynyl, (C₁-C₆)alkoxy, (C₃-C₆)cycloalkoxy,             (C₁-C₆)haloalkoxy, (C₃-C₆)halocycloalkoxy,             (C₂-C₆)alkenyloxy, (C₂-C₆)alkynyloxy, (C₁-C₆)alkylthio,             (C₃-C₆)cycloalkylthio, (C₁-C₆)haloalkylthio,             (C₃-C₆)halocycloalkylthio, (C₁-C₆)alkylamino,             (C₃-C₆)cycloalkylamino, (C₁-C₆)haloalkylamino,             (C₃-C₆)halocycloalkylamino, di(C₁-C₆)alkylamino,             di(C₃-C₆)cycloalkylamino, di(C₁-C₆)haloalkylamino,             di(C₃-C₆)halocycloalkylamino, (C₁-C₆)alkoxy(C₁-C₆)alkyl,             (C₁-C₆)althylthio(C₁-C₆)alkyl,             (C₁-C₆)alkylsulfinyl(C₁-C₆)alkyl,             (C₁-C₆)alkylsulfonyl(C₁-C₆)alkyl,             (C₁-C₆)alkylamino(C₁-C₆)alkyl,             di(C₁-C₆)alkylamino(C₁-C₆)alkyl,             (C₁-C₆)alkylcarbonyl(C₁-C₆)alkyl, cyano(C₁-C₆)alkyl,             optionally substituted phenyl, optionally substituted             1-naphthyl, optionally substituted 2-naphthyl, optionally             substituted phenyl(C₁-C₃)alkyl, optionally substituted             phenyl(C₂-C₃)alkenyl, optionally substituted             naphthyl(C₁-C₃)alkyl, optionally substituted             phenoxy(C₁-C₃)alkyl, optionally substituted phenylamino, and             optionally substituted heterocycle;         -   R² and R³ are independently selected from the group             consisting of hydrogen, cyano, aminocarbonyl, carboxy,             (C₁-C₆)alkyl, (C₃-C₆)cycloalkyl, halo(C₁-C₆)alkyl,             (C₃-C₆)halocycloalkyl, (C₂-C₆)alkenyl, (C₃-C₆)cycloalkenyl,             (C₂-C₆)haloalkenyl, (C₂-C₆)alkynyl, (C₁-C₆)alkylsulfonyl,             (C₁-C₆)alkoxy(C₁-C₆)alkyl, (C₁-C₆)althylthio(C₁-C₆)alkyl,             (C₁-C₆)alkylsulfinyl(C₁-C₆)alkyl,             (C₁-C₆)alkylsulfonyl(C₁-C₆)alkyl,             (C₁-C₆)alkylamino(C₁-C₆)alkyl,             di(C₁-C₆)alkylamino(C₁-C₆)alkyl, (C₁-C₆)alkylcarbonyl,             (C₁-C₆)alkylcarbonyl(C₁-C₆)alkyl, (C₁-C₆)alkylaminocarbonyl,             di(C₁-C₆)alkylaminocarbonyl,             (C₁-C₆)alkylaminocarbonyl(C₁-C₆)alkyl,             di(C₁-C₆)alkylaminocarbonyl(C₁-C₆)alkyl,             (C₁-C₆)alkylcarbonylamino(C₁-C₆)alkyl,             (C₁-C₆)alkoxycarbonyl, (C₁-C₆)alkoxycarbonyl(C₁-C₆)alkyl,             cyano(C₁-C₆)alkyl, hydroxy(C₁-C₆)alkyl, carboxy(C₁-C₆)alkyl,             optionally substituted phenyl, optionally substituted             phenyl(C₁-C₆)alkyl, optionally substituted benzoyl,             optionally substituted naphthyl, optionally substituted             heterocycle, and optionally substituted             heterocyclylcarbonyl, or         -   R² and R³ are joined together with the carbon to which they             are attached to form an unsubstituted or substituted,             partially unsaturated or saturated optionally substituted             3-, 4-, 5-, 6-, 7- or 8-membered carbocyclic or heterocyclic             ring, wherein the heterocyclic ring contains from one to             three heteroatoms selected from O, N, or S;         -   R⁴ is selected from the group consisting of (C₁-C₆)alkyl,             (C₃-C₆)cycloalkyl, (C₁-C₆)haloalkyl, (C₃-C₆)halocycloalkyl,             (C₂-C₆)alkenyl, (C₂-C₆)haloalkenyl, (C₂-C₆)alkynyl,             (C₂-C₆)haloalkynyl, (C₁-C₆)alkoxy, (C₃-C₆)cycloalkoxy,             (C₁-C₆)haloalkoxy, (C₃-C₆)halocycloalkoxy,             (C₂-C₆)alkenyloxy, (C₂-C₆)alkynyloxy, (C₁-C₆)alkylthio,             (C₃-C₆)cycloalkylthio, (C₁-C₆)haloalkylthio,             (C₃-C₆)halocycloalkylthio, (C₁-C₆)alkylamino,             (C₃-C₆)cycloalkylamino, (C₁-C₆)haloalkylamino,             (C₃-C₆)halocycloalkylamino, di(C₁-C₆)alkylamino,             di(C₃-C₆)cycloalkylamino, di(C₁-C₆)haloalkylamino,             di(C₃-C₆)halocycloalkylamino, (C₁-C₆)alkoxy(C₁-C₆)alkyl,             (C₁-C₆)althylthio(C₁-C₆)alkyl,             (C₁-C₆)alkylsulfinyl(C₁-C₆)alkyl,             (C₁-C₆)alkylsulfonyl(C₁-C₆)alkyl,             (C₁-C₆)alkylamino(C₁-C₆)alkyl,             di(C₁-C₆)alkylamino(C₁-C₆)alkyl,             (C₁-C₆)alkylcarbonyl(C₁-C₆)alkyl, cyano(C₁-C₆)alkyl,             optionally substituted phenyl, optionally substituted             1-naphthyl, optionally substituted 2-naphthyl, optionally             substituted phenyl(C₁-C₃)alkyl, optionally substituted             phenyl(C₂-C₃)alkenyl, optionally substituted             naphthyl(C₁-C₃)alkyl, optionally substituted             phenoxy(C₁-C₃)alkyl, optionally substituted phenyl amino,             and optionally substituted heterocycle;         -   R⁵ is selected from the group consisting of (C₁-C₆)alkyl,             (C₃-C₆)cycloalkyl, (C₁-C₆)haloalkyl, (C₃-C₆)halocycloalkyl,             (C₂-C₆)alkenyl, (C₂-C₆)haloalkenyl, (C₂-C₆)alkynyl,             (C₂-C₆)haloalkynyl, (C₁-C₆)alkoxy(C₁-C₆)alkyl,             (C₁-C₆)althylthio(C₁-C₆)alkyl,             (C₁-C₆)alkylsulfinyl(C₁-C₆)alkyl,             (C₁-C₆)alkylsulfonyl(C₁-C₆)alkyl,             (C₁-C₆)alkylamino(C₁-C₆)alkyl,             di(C₁-C₆)alkylamino(C₁-C₆)alkyl,             (C₁-C₆)alkylcarbonyl(C₁-C₆)alkyl, cyano(C₁-C₆)alkyl,             optionally substituted phenyl, optionally substituted             1-naphthyl, optionally substituted 2-naphthyl, optionally             substituted phenyl(C₁-C₃)alkyl, optionally substituted             phenyl(C₂-C₃)alkenyl, optionally substituted             naphthyl(C₁-C₃)alkyl, optionally substituted             phenoxy(C₁-C₃)alkyl, optionally substituted phenylamino, and             optionally substituted heterocycle; and         -   R⁶ and R⁷ are independently selected from the group             consisting of (C₁-C₆)alkyl, (C₃-C₆)cycloalkyl,             (C₁-C₆)haloalkyl, (C₃-C₆)halocycloalkyl, (C₂-C₆)alkenyl,             (C₂-C₆)haloalkenyl, (C₂-C₆)alkynyl, (C₂-C₆)haloalkynyl,             (C₁-C₆)alkoxy, (C₃-C₆)cycloalkoxy, (C₁-C₆)haloalkoxy,             (C₃-C₆)halocycloalkoxy, (C₂-C₆)alkenyloxy,             (C₂-C₆)alkynyloxy, (C₁-C₆)alkylthio, (C₃-C₆)cycloalkylthio,             (C₁-C₆)haloalkylthio, (C₃-C₆)halocycloalkylthio,             (C₁-C₆)alkylamino, (C₃-C₆)cycloalkylamino,             (C₁-C₆)haloalkylamino, (C₃-C₆)halocycloalkylamino,             di(C₁-C₆)alkylamino, di(C₃-C₆)cycloalkylamino,             di(C₁-C₆)haloalkylamino, di(C₃-C₆)halocycloalkylamino,             (C₁-C₆)alkoxy(C₁-C₆)alkyl, (C₁-C₆)althylthio(C₁-C₆)alkyl,             (C₁-C₆)alkylsulfinyl(C₁-C₆)alkyl,             (C₁-C₆)alkylsulfonyl(C₁-C₆)alkyl,             (C₁-C₆)alkylamino(C₁-C₆)alkyl,             di(C₁-C₆)alkylamino(C₁-C₆)alkyl,             (C₁-C₆)alkylcarbonyl(C₁-C₆)alkyl, cyano(C₁-C₆)alkyl,             optionally substituted phenyl, optionally substituted             phenyl(C₁-C₆)alkyl, optionally substituted heterocycle,             optionally substituted phenoxy, optionally substituted             heterocycloxy, optionally substituted phenylthio, optionally             substituted heterocyclylthio, optionally substituted             naphthyl, optionally substituted phenylamino, optionally             substituted heterocyclylamino, optionally substituted             N-phenyl-N—(C₁-C₆)alkylamino, and optionally substituted             N-heterocyclyl-N—(C₁-C₆)alkylamino.

In another embodiment, the activating ligand is a compound having Formula V, wherein:

-   -   Q¹ is O;     -   R¹ is substituted phenyl wherein the substituents are         independently selected from the group consisting of (C₁-C₂)alkyl         and (C₁-C₂)alkoxy; or two adjacent positions are joined together         with the atoms to which they are attached to form an         unsubstituted or substituted, unsaturated, partially         unsaturated, or saturated 5-, 6- or 7-membered carbocyclic or         heterocyclic ring, wherein the heterocyclic ring contains from         one to two oxygen atoms and one to four substituents are         independently selected from the group consisting of: cyano,         (C₁-C₂)alkyl, (C₁-C₂)alkylamino, di(C₁-C₂)alkylamino,         (C₁-C₂)alkoxycarbonyl, (C₁-C₂)alkylaminocarbonyl,         di(C₁-C₂)alkylaminocarbonyl, oxo, and methoxyimino;     -   R² and R³ are independently selected from the group consisting         of (C₁-C₆)alkyl, (C₃-C₆)cycloalkyl, halo(C₁-C₆)alkyl,         (C₁-C₃)alkoxy(C₁-C₃)alkyl, (C₁-C₃)althylthio(C₁-C₃)alkyl,         (C₁-C₃)alkylsulfinyl(C₁-C₃)alkyl,         (C₁-C₃)alkylsulfonyl(C₁-C₃)alkyl, (C₁-C₃)alkylamino(C₁-C₃)alkyl,         di(C₁-C₃)alkylamino(C₁-C₃)alkyl, (C₁-C₆)alkylcarbonyl,         (C₁-C₃)alkylcarbonyl(C₁-C₃)alkyl, (C₁-C₆)alkylaminocarbonyl,         di(C₁-C₆)alkylaminocarbonyl,         (C₁-C₃)alkylaminocarbonyl(C₁-C₃)alkyl,         di(C₁-C₃)alkylaminocarbonyl(C₁-C₃)alkyl,         (C₁-C₃)alkylcarbonylamino(C₁-C₃)alkyl, (C₁-C₆)alkoxycarbonyl,         and C₁-C₃)alkoxycarbonyl(C₁-C₃)alkyl; or     -   R² and R³ may be joined together with the carbon to which they         are attached to form an unsubstituted or substituted, partially         unsaturated or saturated 5-, 6- or 7-membered carbocyclic or         heterocyclic ring, wherein the heterocyclic ring contains one         heteroatom selected from O or S; and one to four substituents         are independently selected from the group consisting of         (C₁-C₃)alkyl, (C₁-C₃)alkylamino, di(C₁-C₃)alkylamino,         (C₁-C₄)alkoxy carbonyl, (C₁-C₃)alkylaminocarbonyl, and         di(C₁-C₃)alkylaminocarbonyl; and     -   R⁴ is selected from optionally substituted phenyl or pyridyl         wherein the substituents are independently selected from the         group consisting of (C₁-C₃)alkyl and (C₁-C₃)alkoxy;

In another embodiment, the activating ligand is a compound having Formula V, wherein Q is oxygen, and R¹, R², R³, and R⁴ are defined according to Table 5.

TABLE 5 Ligand Components R¹ R² R³ R⁴ 2-Me-3-MeO—Ph —(CH₂)₄— Ph 2-Me-3-MeO—Ph —(CH₂)₄— 3-Me—Ph 4-Et—Ph —(CH₂)₄— Ph 2-Me-3-MeO—Ph —(CH₂)₅— 3-MeO—Ph 2-Me-3-MeO—Ph —(CH₂)₄— 3-MeO—Ph 2-Me-3-MeO—Ph —(CH₂)₃— 3-Me—Ph 2-Me-3-MeO—Ph —(CH₂)₅— 3-Me—Ph 2-Me-3-MeO—Ph Bn Me 3-Me—Ph 2-Me-3-MeO—Ph —(CH₂)₂— 3-Me—Ph 2-Me-3-MeO—Ph —(CH₂)₄— 3,5-diMe—Ph 2-Me-3-MeO—Ph —(CH₂)₅— 3,5-diMe—Ph 2-Me-3-MeO—Ph Bn Me 3,5-diMe—Ph 2-Me-3-MeO—Ph —(CH₂)₂— 3,5-diMe—Ph 2-Me-3-MeO—Ph —(CH₂)₃— 3,5-diMe—Ph 2-Me-3-MeO—Ph —(CH₂)₅— 4-Me—Ph 2-Me-3-MeO—Ph Bn Me 4-Me—Ph 2-Me-3-MeO—Ph —(CH₂)₄— 3-Me-4-F—Ph 2-Me-3-MeO—Ph —(CH₂)₅— 3-Me-4-F—Ph 2-Me-3-MeO—Ph —(CH₂)₂— 3-Me-4-F—Ph 2-Me-3-MeO—Ph i-Pr Me 3,5-diMe—Ph 2-Et-3-MeO—Ph —(CH₂)₄— Ph 2-Et-3,6-OCH₂CH₂O—Ph —(CH₂)₄— Ph 2-Me-3,4-OCH₂O—Ph —(CH₂)₄— Ph 2-Me-3-MeO—Ph —(CH₂)₂— 4-Me—Ph 2-Me-3-MeO—Ph —CH₂CH₂OCH₂CH₂— 3-Me—Ph 2-Me-3-MeO—Ph —CH₂CH₂SCH₂CH₂— 3-Me—Ph 2-Me-3-MeO—Ph —CH₂CH₂OCH₂CH₂— 3,5-diMe—Ph 2-Me-3-MeO—Ph —CH₂CH₂SCH₂CH₂— 3,5-diMe—Ph 2-Me-3-MeO—Ph —CH₂CH₂C(OCH₂CH₂O)CH₂CH₂— 3,5-diMe—Ph 2-Me-3-MeO—Ph i-Pr Me 2-MeO—Ph 2-Me-3-MeO—Ph i-Pr Me 3-Me—Ph 2-Me-3-MeO—Ph i-Pr Me 3-MeO—Ph 2-Me-3-MeO—Ph i-Pr Me 4-Me—Ph 2-Me-3-MeO—Ph i-Pr Me Ph 2-Me-3-MeO—Ph —CH₂CH₂C(OCH₂CH₂O)CH₂CH₂— 3-Me—Ph 2-Me-3-MeO—Ph Et Et 2-Me—Ph 2-Me-3-MeO—Ph Et Et 2-MeO—Ph 2-Me-3-MeO—Ph Et Et 4-F—Ph 2-Me-3-MeO—Ph —(CH₂)₄— 2-Me—Ph 2-Me-3-MeO—Ph —(CH₂)₄— 2-MeO—Ph 2-Me-3-MeO—Ph —(CH₂)₄— 4-MeO—Ph 2-Me-3-MeO—Ph —(CH₂)₄— 4-F—Ph 2-Me-3-MeO—Ph —(CH₂)₄— 3,4-OCH₂O—Ph 2-Me-3-MeO—Ph —(CH₂)₅— 2-Me—Ph 2-Me-3-MeO—Ph —(CH₂)₅— 2-MeO—Ph 2-Me-3-MeO—Ph —(CH₂)₅— 4-MeO—Ph 2-Me-3-MeO—Ph —(CH₂)₅— 3,4-OCH₂O—Ph 2-Me-3-MeO—Ph Et Et 3-Me—Ph 2-Me-3-MeO—Ph Et Et 3-MeO—Ph 2-Me-3-MeO—Ph Et Et 3-Me-4-F—Ph 2-Me-3-MeO—Ph Et Et 3,5-diMe—Ph 2-Me-3-MeO—Ph i-Bu Me 3-Me—Ph 2-Me-3-MeO—Ph i-Bu Me 3-MeO—Ph 2-Me-3-MeO—Ph i-Bu Me 3-Me-4-F—Ph 2-Me-3-MeO—Ph i-Bu Me 3,5-diMe—Ph 2-Me-3-MeO—Ph i-Pr Me 3-Me-4-F—Ph 2-Me-3-MeO—Ph Ph i-Pr 3-Me—Ph 2-Me-3-MeO—Ph Et Et 4-MeO—Ph 2-Me-3-MeO—Ph Et Et 3,4-OCH2O—Ph 2-Me-3-MeO—Ph —(CH₂)₅— 4-F—Ph 2-Me-3-MeO—Ph —CH₂CH₂C(=O)CH₂CH₂— 3-Me—Ph 2-Me-3-MeO—Ph —CH₂CH₂S(=O)₂CH₂CH₂— 3,5-diMe—Ph 2-Me-3-MeO—Ph i-Pr Me 2-Me—Ph 2-Me-3-MeO—Ph —(CH₂)₅— 2,6-diMeO-3-pyridyl 2-Me-3-MeO—Ph —(CH₂)₄— 3,5-diMeO-4-Me—Ph 2-Me-3-MeO—Ph —(CH₂)₅— 3,5-diMeO-4-Me—Ph 2-Me-3-MeO—Ph —(CH₂)₄— 3-MeO-4,5-diF—Ph 2-Me-3-MeO—Ph —(CH₂)₅— 3-MeO-4,5-diF—Ph 2-Me-3-MeO—Ph —(CH₂)₅— Ph 2-Me-3-MeO—Ph —(CH₂)₆— 2-MeO—Ph 2-Me-3-MeO—Ph —(CH₂)₆— 3,5-diMe—Ph 2-Me-3-MeO—Ph 4-F—Ph Me 2-MeO—Ph 2-Me-3-MeO—Ph 4-F—Ph Me 3,5-diMe—Ph 2-Me-3-MeO—Ph Me Me 2-MeO—Ph 2-Me-3-MeO—Ph Me Me 3,5-diMe—Ph 2-Me-3-MeO—Ph Me Me Ph 2-Me-3-MeO—Ph Et Et 4-Me—Ph 2-Me-3-MeO—Ph Et Et Ph 2-Me-3-MeO—Ph —(CH₂)₄— 4-Me—Ph 2-Et-3,4-OCH₂CH₂O—Ph —(CH₂)₅— 3,5-di-Me—Ph 2-Me-3,4-OCH₂O—Ph —(CH₂)₅— 3,5-di-Me—Ph 3,4-OCH₂CH₂O—Ph —(CH₂)₅— 3,5-di-Me—Ph 3,4-CH₂OCH₂O—Ph —(CH₂)₅— 3,5-di-Me—Ph 2-Et-3,4-OCH₃CH₂O—Ph —(CH₂)₄— 3,5-di-Me—Ph 2-Me-3,4-OCH₂O—Ph —(CH₂)₄— 3,5-di-Me—Ph 3,4-OCH₂CH₂O—Ph —(CH₂)₄— 3,5-di-Me—Ph 3,4-CH₂OCH₂O—Ph —(CH₂)₄— 3,5-di-Me—Ph 3,4-OCH₂O—Ph —(CH₂)₄— 3,5-di-Me—Ph 2-Me—Ph —(CH₂)₄— 3,5-di-Me—Ph Ph t-Bu H 4-Cl—Ph 4-Cl—Ph —(CH₂)₄— Ph Me Ph H 4-Me—Ph Me 4-Me—Ph H Ph Me Ph H Ph 4-Cl—Ph Me Me Ph 4-Me—Ph t-Bu H Ph 2,3-di-Me—Ph t-Bu H Ph 4-NO₂—Ph t-Bu H Ph 2-Me-3-MeO—Ph —(CH₂)₂— 3-MeO—Ph 2-Me-3-MeO—Ph Benzyl Me 3-MeO—Ph 2-Me-3-MeO—Ph —(CH₂)₂— 2-Me—Ph 3-Me-benzofuran-2-yl —(CH₂)₄— Ph Ph Me Me Ph 2-Me—Ph Me Me Ph 3,4-OCH₂O—Ph Me Me Ph 3-MeO—Ph Me Me Ph 4-Et—Ph Me Me Ph 2-Me-3-MeO—Ph —CH₂CH₂N(C(O)OtBu)CH₂CH₂— 3-Me—Ph 2-Me-3-MeO—Ph —CH₂CH₂N(C(O)OtBu)CH₂CH₂— 3,5-di-Me—Ph 2-Me-3-MeO—Ph i-Pr Me 3,4-OCH₂O—Ph 2-Me-3-MeO—Ph i-Pr Me Me 2-Me-3-MeO—Ph t-Bu H 3-Me—Ph 2-Me-3-MeO—Ph t-Bu H 3-MeO—Ph 2-Me-3-MeO—Ph t-Bu H 3,5-di-Me—Ph 2-MeO—Ph Me Me 3-Me—Ph 2-MeO—Ph Me Me 3-MeO—Ph 2-Me-3-MeO—Ph i-Bu Me 4-MeO—Ph 2-MeO—Ph Me Me 3,5-di-Me—Ph 2-Me-3-MeO—Ph (CH₂)₅ n-Bu Ph Me Me Et 3-MeO—Ph Me Me Et 3,4-OCH₂O—Ph Me Me Et 2-Me—Ph Me Me El 4-Et—Ph Me Me Et Ph Me Me 3,5-di-Me—Ph 2-Me—Ph Me Me 3,5-di-Me—Ph 3-MeO—Ph Me Me 3,5-di-Me—Ph 4-Et—Ph Me Me 3,5-di-Me—Ph 3,4-OCH₂O—Ph Me Me 3,5-di-Me—Ph Ph —(CH₂)₄— Et 2-Me—Ph —(CH₂)₄— Et 3-MeO—Ph —(CH₂)₄— Et 4-Et—Ph —(CH₂)₄— Et 3,4-OCH₂O—Ph —(CH₂)₄— Et Ph —(CH₂)₄— 3,5-di-Me—Ph 3-MeO—Ph —(CH₂)₄— 3,5-di-Me—Ph 4-Et—Ph —(CH₂)₄— 3,5-di-Me—Ph Ph —(CH₂)₄— Ph 2-Me—Ph —(CH₂)₄— Ph 3-MeO—Ph —(CH₂)₄— Ph 3,4-OCH₂O—Ph —(CH₂)₄— Ph 2-Et-3-MeO—Ph —(CH₂)₅— 3,5-di-Me—Ph 2-Et-3-MeO—Ph —(CH₂)₄— 3,5-di-Me—Ph CF₃ —(CH₂)₄— 3,5-di-Me—Ph 2-Me-3-MeO—Ph —CH₂N[(C═O)Ot-Bu]CH₂CH₂CH₂— 3,5-di-Me—Ph 2-Me-3-MeO—Ph —CH₂CH₂NHCH₂CH₂— 3,5-di-Me—Ph 2-Me-3-MeO—Ph —CH₂NHCH₂CH₂CH₂— 3,5-di-Me—Ph 2-Me-3-MeO—Ph —CH₂CH₂N[(C═O)CH₃]CH₂CH₂— 3,5-di-Me—Ph 2-Me-3-MeO—Ph —CH₂CH₂N[(C═O)(C═O)OEt]CH₂CH₂— 3,5-di-Me—Ph 2-Me-3-MeO—Ph —CH₂CH₂N[S(O)₂CH₃]CH₂CH₂— 3,5-di-Me—Ph 2-Me-3-MeO—Ph —CH₂CH₂N[CH₂(C═O)OEt]CH₂CH₂— 3,5-di-Me—Ph 2-Me-3-MeO—Ph —CH₂N[(C═O)CH₃]CH₂CH₂CH₂— 3,5-di-Me—Ph 2-Me-3-MeO—Ph —CH₂N[(C═O)(C═O)OEt]CH₂CH₂CH₂— 3,5-di-Me—Ph 2-Me-3-MeO—Ph —CH₂N[S(O)₂CH₃]CH₂CH₂CH₂— 3,5-di-Me—Ph 2-Me-3-MeO—Ph —CH₂N[CH₂(C═O)OCH₃]CH₂CH₂CH₂— 3,5-di-Me—Ph 2-Me-3-MeO—Ph —CH₂CH₂N[(C═O)NHEt]CH₂CH₂— 3,5-di-Me—Ph 2-Me-3-MeO—Ph —CH₂CH₂N[(C═O)OiPr]CH₂CH₂— 3,5-di-Me—Ph 2-Me-3-MeO—Ph —CH₂CH₂N[CH₂CN]CH₂CH₂— 3,5-di-Me—Ph 2-Me-3-MeO—Ph —CH₂N[(C═O)NHEt]CH₂CH₂CH₂— 3,5-di-Me—Ph 2-Me-3-MeO—Ph —CH₂CH₂CH₂N(CH₃)CH₂— 3,5-di-Me—Ph 2-NH₂—Ph Et H Ph 4-Et—Ph —(CH₂)₅— 3,5-di-Cl—Ph 2-Me-3-MeO—Ph —(CH₂)₅— 2-MeO-5-F—Ph 2-Me-3-MeO—Ph —(CH₂)₅— 2-MeO-5-Me—Ph 2-Me-3-MeO—Ph —(CH₂)₅— 2,5-di-MeO—Ph 2-Me-3-MeO—Ph —(CH₂)₅— 4-Me-2-pyridyl 2-Me-3-MeO—Ph —(CH₂)₅— 6-Me-2-pyridyl 4-Et—Ph —(CH₂)₅— 2-MeO-5-F—Ph 4-Et—Ph —(CH₂)₅— 2-MeO-5-Me—Ph 4-Et—Ph —(CH₂)₅— 2,5-di-MeO—Ph 4-Et—Ph —(CH₂)₅— 4-Me-2-pyridyl 4-Et—Ph —(CH₂)₅— 6-Me-2-pyridyl 4-Et—Ph —(CH₂)₅— 2-MeO—Ph 4-Et—Ph —(CH₂)₅— 3,5-di-Me—Ph 4-Et—Ph —(CH₂)₅— 3-Me—Ph 2-Me-3-MeO—Ph i-Pr Et 2-MeO—Ph 2-Me-3-MeO—Ph i-Pr Et 3,5-di-Me—Ph

In another embodiment, the activating ligand is a compound having Formula VI, wherein n is 2, and R², R³, R⁴, and R⁵ are defined according to Table 6.

TABLE 6 Ligand Components R²/R³ R⁴ R⁵ —(CH₂)₅— 3,5-di-Me—Ph 4H-benzo[1,3]dioxine-6-yl —(CH₂)₄— 3,5-di-Me—Ph 4-Me—Ph —(CH₂)₅— 3,5-di-Cl—Ph 4-Me—Ph —(CH₂)₅— 3,5-di-Cl—Ph 3-MeO—Ph

In another embodiment, the activating ligand is a compound having Formula VIII:

wherein:

-   -   X and X′ are independently O or S;     -   R¹ is selected from the group consisting of hydrogen,         (C₁-C₆)alkyl, (C₁-C₆)haloalkyl, (C₁-C₆)cyanoalkyl,         (C₁-C₆)alkoxycarbonyl(C₁-C₆)alkyl, (C₁-C₆)alkoxy, benzyloxy,         optionally substituted phenyl, optionally substituted naphthyl         wherein the substituents are independently 1 to 3 halo, nitro,         (C₁-C₆) alkoxy, (C₁-C₆)alkyl, or amino, optionally substituted         benzothiophene-2-yl, benzothiophene-3-yl, benzofuran-2-yl, or         benzofuran-3-yl wherein the substituents are independently 1 to         3 halo, nitro, hydroxy, (C₁-C₆)alkyl, (C₁-C₆)alkoxy, carboxy, or         (C₁-C₆)alkoxycarbonyl (—CO₂R^(a)), optionally substituted 2-,         3-, or 4-pyridyl wherein the substituents are independently 1 to         3 halo, cyano, nitro, hydroxy, (C₁-C₆)alkyl, (C₁-C₆)alkoxy, or         (C₁-C₆)haloalkoxy, optionally substituted 5-membered heterocycle         selected from furyl, thiophenyl, triazolyl, pyrrolyl,         isopyrrolyl, pyrazolyl, isoimidazolyl, thiazolyl, isothiazolyl,         oxazolyl, or isooxazolyl wherein the substituents are         independently 1 to 3 halo, nitro, hydroxy, (C₁-C₆)alkyl,         (C₁-C₆)alkoxy, carboxy, (C₁-C₆)alkoxycarbonyl (—CO₂R^(a)), or         unsubstituted or substituted phenyl wherein the substituents are         independently 1 to 3 halo, nitro, (C₁-C₆)alkyl,         (C₁-C₆)haloalkyl, (C₁-C₆)alkoxy, (C₁-C₆)haloalkoxy, carboxy,         (CC₁-C₄)alkoxycarbonyl (—CO₂R^(a)), or amino (—NR^(a)R^(b)),         aromatic substituted or unsubstituted phenyl(C₁-C₆)alkyl,         phenyl(C₁-C₆)alkoxy(C₁-C₆)alkyl, or phenoxy(C₁-C₆)alkyl wherein         the aromatic substituents are independently 1 to 3 halo, nitro,         (C₁-C₆) alkoxy, (C₁-C₆)alkyl, or amino, and aromatic substituted         or unsubstituted phenylamino, phenyl(C₁-C₆)alkylamino, or         phenylcarbonylamino wherein the aromatic substituents are         independently 1 to 3 halo, nitro, (C₁-C₆)alkoxy, (C₁-C₆)alkyl,         or amino;     -   wherein R^(a), R^(b), and R^(c) are independently H,         (C₁-C₆)alkyl, or phenyl;     -   R² and R³ are independently H, (C₁-C₆)alkyl, (C₁-C₆)haloalkyl,         (C₁-C₆)cyanoalkyl, (C₁-C₆)hydroxyalkyl,         (C₁-C₆)alkoxy(C₁-C₆)alkyl, phenyl, or together as an alkane         linkage (—(CH₂)_(x)—), an alkyloxylalkyl linkage         (—(CH₂)_(y)O(CH₂)_(z)—), an alkylaminoalkyl linkage         (—(CH₂)_(y)NR^(a)(CH₂)_(z)—), or an alkylbenzoalkyl linkage         (—(CH₂)_(y)-1-benzo-2-(CH₂)_(z)—) form a ring with the carbon         atom to which they are attached, wherein x=3 to 7, y=1 to 3, z=1         to 3, and R^(a) is H, (C₁-C₆)alkyl, or phenyl; and     -   R⁴ is optionally substituted phenyl, wherein the substituents         are independently 1 to 5 H; halo; nitro; cyano; hydroxy; amino         (—NR^(a)R^(b)); (C₁-C₆)alkyl; (C₁-C₆)haloalkyl;         (C₁-C₆)cyanoalkyl; (C₁-C₆)hydroxyalkyl, (C₁-C₆)alkoxy; phenoxy;         (C₁-C₆)haloalkoxy; (C₁-C₆)alkoxy(C₁-C₆)alkyl;         (C₁-C₆)alkoxy(C₁-C₆)alkoxy; (C₁-C₆)alkanoyloxy(C₁-C₆)alkyl;         (C₂-C₆)alkenyl optionally substituted with halo, cyano, (C₁-C₄)         alkyl, or (C₁-C₄)alkoxy; (C₂-C₆)alkynyl optionally substituted         with halo or (C₁-C₄)alkyl; formyl; carboxy;         (C₁-C₆)alkylcarbonyl; (C₁-C₆)haloalkylcarbonyl; benzoyl;         (C₁-C₆)alkoxycarbonyl; (C₁-C₆)haloalkoxycarbonyl;         (C₁-C₆)alkanoyloxy (—OCOR^(a)); carboxamido (—CONR^(a)R^(b));         amido (—NR^(a)COR^(b)); alkoxycarbonylamino (—NR^(a)CO₂R^(b));         alkylaminocarbonylamino (—NR^(a)CONR^(b)R^(c)); mercapto;         (C₁-C₆)alkylthio; (C₁-C₆) alkylsulfonyl, (C₁-C₆)alkylsulfoxido         (—S(O)R^(a)); sulfamido (—SO₂NR^(a)R^(b)); or optionally         substituted phenyl wherein the substituents are independently 1         to 3 halo, nitro, (C₁-C₆) alkoxy, (C₁-C₆)alkyl, or amino, or         when two adjacent positions on the phenyl ring are substituted         with alkoxy groups, these groups, together with the carbon atoms         to which they are attached, may be joined to form a 5- or         6-membered dioxolano (—OCH₂O—) or dioxano (—OCH₂CH₂O—)         heterocyclic ring; wherein R^(a), R^(b), and R^(c) are         independently H, (C₁-C₆)alkyl, or phenyl.

In another embodiment, the activating ligand is a compound having Formula VIII, wherein:

-   -   X and X′ are O;     -   R¹ is phenyl, 4-chlorophenyl-, 4-ethylphenyl-,         2-ethyl-3,4-ethylenedioxyphenyl, 3-fluorophenyl-,         2-fluoro-4-ethylphenyl-, 2-methyl-3-methoxyphenyl-,         2-ethyl-3-methoxyphenyl, 3-methylphenyl-, 2-methoxyphenyl-,         2-nitrophenyl-, 3-nitrophenyl-, 2-furanyl-, benzyl-,         benzothiophene-2-yl-, phenylamino-, benzyloxymethyl,         phenoxymethyl-, 3-toluoylamino-, benzylamino-, benzoylamino-,         ethoxycarbonylethyl-, or 3-chloro-2,2,3,3-tetrafluoroethyl;     -   R² and R³ are independently methyl, ethyl, or together as a         tetramethylene (—(CH₂)₄—), 4-pyrano (—CH₂CH₂OCH₂CH₂—), or         methylenebenzoethylene (—CH₂-1-benzo-2-CH₂CH₂—) linkage form a         ring with the carbon atom to which they are attached; and     -   R⁴ is phenyl, 4-biphenyl, 4-chlorophenyl, 2,4-dimethoxyphenyl,         3,5-dimethylphenyl, 2-methoxyphenyl, 3,4-methylenedioxyphenyl,         3-trifluoromethylphenyl, or 4-trifluromethoxyphenyl;

In another embodiment, the activating ligand is a compound having Formula VIII selected from the group consisting of:

-   1-[5,5-Dimethyl-3-(3-trifluoromethyl-phenyl)-[1,2,4]oxadiazol-4-yl]-3-phenyl-urea; -   N-[3-(3,5-Dimethyl-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-3-fluoro-benzamide; -   Furan-2-carboxylic acid     [3-(3,5-dimethyl-phenyl)-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl]-amide; -   3-Chloro-N-[3-(3,5-dimethyl-phenyl)-5-ethyl-5-methyl-[1,2,4]oxadiazol-4-yl]-2,2,3,3-tetrafluoro-propionamide; -   N-[3-(3,5-Dimethyl-phenyl)-1,8-dioxa-2,4-diaza-spiro[4.5]dec-2-en-4-yl]-4-ethyl-benzamide; -   2-Benzyloxy-N-[5,5-dimethyl-3-(3-trifluoromethyl-phenyl)-[1,2,4]oxadiazol-4-yl]-acetamide; -   N-[3-(3,5-Dimethyl-phenyl)-1,8-dioxa-2,4-diaza-spiro[4.5]dec-2-en-4-yl]-2-ethyl-3-methoxy-benzamide; -   2-Benzyloxy-N-[3-(3,5-dimethyl-phenyl)-1,8-dioxa-2,4-diaza-spiro[4.5]dec-2-en-4-yl]-acetamide; -   N-[3-(3,5-Dimethyl-phenyl)-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl]-benzamide; -   Furan-2-carboxylic acid     [3-(2-methoxy-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-amide; -   2-Phenoxy-N-(3-phenyl-1,8-dioxa-2,4-diaza-spiro[4.5]dec-2-en-4-yl)-acetamide; -   N-(3-Phenyl-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl)-succinamic acid     ethyl ester; -   N-[5,5-Dimethyl-3-(3-trifluoromethyl-phenyl)-[1,2,4]oxadiazol-4-yl]-benzamide; -   2-Ethyl-3-methoxy-N-[3-(2-methoxy-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-benzamide; -   1-(3-Benzo[1,3]dioxol-5-yl-5,5-dimethyl-[1,2,4]oxadiazol-4-yl)-3-phenyl-urea; -   2-Benzyloxy-N-[3-(2-methoxy-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-acetamide; -   N-[3-(3,5-Dimethyl-phenyl)-1,8-dioxa-2,4-diaza-spiro[4.5]dec-2-en-4-yl]-benzamide; -   N-(3-Biphenyl-4-yl-5,5-dimethyl-[1,2,4]oxadiazol-4-yl)-2-ethyl-3-methoxy-benzamide; -   N-[5,5-Dimethyl-3-(3-trifluoromethyl-phenyl)-[1,2,4]oxadiazol-4-yl]-2-phenyl-acetamide; -   N-[5,5-Dimethyl-3-(4-trifluoromethoxy-phenyl)-[1,2,4]oxadiazol-4-yl]-2-ethyl-3-methoxy-benzamide; -   N-(3-Benzo[1,3]dioxol-5-yl-5,5-dimethyl-[1,2,4]oxadiazol-4-yl)-2-ethyl-3-methoxy-benzamide; -   4-Chloro-N-[3-(3,5-dimethyl-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-benzamide; -   1-[3-(2-Methoxy-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-3-phenyl-urea; -   4-Ethyl-N-[3-(2-methoxy-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-benzamide; -   1-Phenyl-3-(3-phenyl-1,8-dioxa-2,4-diaza-spiro[4.5]dec-2-en-4-yl)-urea; -   N-[5,5-Dimethyl-3-(4-trifluoromethoxy-phenyl)-[1,2,4]oxadiazol-4-yl]-2-phenoxy-acetamide; -   2-Phenyl-N-(3-phenyl-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl)-acetamide; -   N-[3-(3,5-Dimethyl-phenyl)-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl]-succinamic     acid ethyl ester; -   N-[5,5-Dimethyl-3-(4-trifluoromethoxy-phenyl)-[1,2,4]oxadiazol-4-yl]-benzamide; -   2-Benzyloxy-N-(3-phenyl-1,8-dioxa-2,4-diaza-spiro[4.5]dec-2-en-4-yl)-acetamide; -   N-[3-(4-Chloro-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-4-ethyl-benzamide; -   N-[3-(3,5-Dimethyl-phenyl)-1-oxa-2,4-diaza-spiro[4.5]-7,8-benzo-dec-2-en-4-yl]-3-methoxy-2-methyl-benzamide; -   N-[3-(2,4-Dimethoxy-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-succinamic     acid ethyl ester; -   N-[3-(3,5-Dimethyl-phenyl)-5-ethyl-5-methyl-[1,2,4]oxadiazol-4-yl]-benzamide; -   N-[3-(3,5-Dimethyl-phenyl)-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl]-4-ethyl-benzamide; -   N-[3-(3,5-Dimethyl-phenyl)-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl]-2-phenoxy-acetamide; -   N-(5,5-Dimethyl-3-phenyl-[1,2,4]oxadiazol-4-yl)-3-methoxy-2-methyl-benzamide; -   N-(3-Phenyl-1,8-dioxa-2,4-diaza-spiro[4.5]dec-2-en-4-yl)-benzamide; -   N-[3-(3,5-Dimethyl-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-3-methoxy-2-methyl-benzamide; -   N-[3-(3,5-Dimethyl-phenyl)-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl]-2-phenyl-acetamide; -   Benzo[b]thiophene-2-carboxylic acid     [3-(2-methoxy-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-amide; -   N-[3-(3,5-Dimethyl-phenyl)-1,8-dioxa-2,4-diaza-spiro[4.5]dec-2-en-4-yl]-2-phenoxy-acetamide; -   N-[3-(3,5-Dimethyl-phenyl)-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl]-2-ethyl-3-methoxy-benzamide; -   2-Benzyloxy-N-[3-(3,5-dimethyl-phenyl)-5-ethyl-5-methyl-[1,2,4]oxadiazol-4-yl]-acetamide; -   1-[3-(3,5-Dimethyl-phenyl)-5-ethyl-5-methyl-[1,2,4]oxadiazol-4-yl]-3-phenyl-urea; -   2-Benzyloxy-N-[3-(3,5-dimethyl-phenyl)-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl]-acetamide; -   1-[3-(3,5-Dimethyl-phenyl)-1,8-dioxa-2,4-diaza-spiro[4.5]dec-2-en-4-yl]-3-phenyl-urea; -   N-[5,5-Dimethyl-3-(4-trifluoromethoxy-phenyl)-[1,2,4]oxadiazol-4-yl]-4-ethyl-benzamide; -   1-[3-(3,5-Dimethyl-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-3-m-tolyl-urea; -   N-[3-(2-Methoxy-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-2-phenoxy-acetamide; -   N-[3-(2,4-Dimethoxy-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-2-ethyl-3-methoxy-benzamide; -   3-Chloro-N-[5,5-dimethyl-3-(3-trifluoromethyl-phenyl)-[1,2,4]oxadiazol-4-yl]-2,2,3,3-tetrafluoro-propionamide; -   N-[3-(3,5-Dimethyl-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-4-ethyl-benzamide; -   N-(3-Benzo[1,3]dioxol-5-yl-5,5-dimethyl-[1,2,4]oxadiazol-4-yl)-4-ethyl-benzamide; -   3-Chloro-2,2,3,3-tetrafluoro-N-[3-(2-methoxy-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-propionamide; -   3-Chloro-2,2,3,3-tetrafluoro-N-(3-phenyl-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl)-propionamide; -   2-Benzyloxy-N-[5,5-dimethyl-3-(4-trifluoromethoxy-phenyl)-[1,2,4]oxadiazol-4-yl]-acetamide; -   1-[3-(4-Chloro-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-3-phenyl-urea; -   N-[3-(3,5-Dimethyl-phenyl)-5-ethyl-5-methyl-[1,2,4]oxadiazol-4-yl]-2-ethyl-3-methoxy-benzamide; -   Furan-2-carboxylic acid     [5,5-dimethyl-3-(3-trifluoromethyl-phenyl)-[1,2,4]oxadiazol-4-yl]-amide; -   Furan-2-carboxylic acid     (3-phenyl-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl)-amide; -   1-[3-(3,5-Dimethyl-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-3-phenyl-urea; -   3-Chloro-N-[3-(4-chloro-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-2,2,3,3-tetrafluoro-propionamide, -   N-[3-(3,5-Dimethyl-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-2-methoxy-benzamide; -   2-Ethyl-N-(5-ethyl-5-methyl-3-phenyl-[1,2,4]oxadiazol-4-yl)-3-methoxy-benzamide; -   N-[3-(3,5-Dimethyl-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-3-methyl-benzamide; -   N-[3-(2,4-Dimethoxy-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-2-phenyl-acetamide; -   N-[3-(2,4-Dimethoxy-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-2-phenoxy-acetamide; -   N-[3-(3,5-Dimethyl-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-2-ethyl-3-methoxy-benzamide; -   N-(3-Benzo[1,3]dioxol-5-yl-5,5-dimethyl-[1,2,4]oxadiazol-4-yl)-2-phenyl-acetamide; -   Furan-2-carboxylic acid     [3-(4-chloro-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-amide; -   N-(3-Benzo[1,3]dioxol-5-yl-5,5-dimethyl-[1,2,4]oxadiazol-4-yl)-succinamic     acid ethyl ester; -   N-[3-(3,5-Dimethyl-phenyl)-1,8-dioxa-2,4-diaza-spiro[4.5]dec-2-en-4-yl]-2-phenyl-acetamide; -   N-[3-(3,5-Dimethyl-phenyl)-1,8-dioxa-2,4-diaza-spiro[4.5]dec-2-en-4-yl]-3-methoxy-2-methyl-benzamide; -   Benzo[b]thiophene-2-carboxylic acid     [3-(4-chloro-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-amide; -   1-Benzyl-3-[3-(3,5-dimethyl-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-urea; -   N-(3-Phenyl-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl)-benzamide; -   3-Chloro-N-[3-(3,5-dimethyl-phenyl)-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl]-2,2,3,3-tetrafluoro-propionamide; -   N-[3-(3,5-Dimethyl-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-3-nitro-benzamide; -   2-Ethyl-3-methoxy-N-(3-phenyl-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl)-benzamide; -   N-[5,5-Dimethyl-3-(3-trifluoromethyl-phenyl)-[1,2,4]oxadiazol-4-yl]-2-ethyl-3-methoxy-benzamide; -   Furan-2-carboxylic acid     [5,5-dimethyl-3-(4-trifluoromethoxy-phenyl)-[1,2,4]oxadiazol-4-yl]-amide; -   1-(5-Ethyl-5-methyl-3-phenyl-[1,2,4]oxadiazol-4-yl)-3-phenyl-urea; -   N-[3-(2,4-Dimethoxy-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-benzamide; -   N-[3-(3,5-Dimethyl-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-2-nitro-benzamide; -   N-[3-(4-Chloro-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-2-ethyl-3-methoxy-benzamide; -   Furan-2-carboxylic acid     (5-ethyl-5-methyl-3-phenyl-[1,2,4]oxadiazol-4-yl)-amide; -   Furan-2-carboxylic acid     [3-(2,4-dimethoxy-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-amide; -   N-(5-Ethyl-5-methyl-3-phenyl-[1,2,4]oxadiazol-4-yl)-2-phenoxy-acetamide; -   Furan-2-carboxylic acid     [3-(3,5-dimethyl-phenyl)-5-ethyl-5-methyl-[1,2,4]oxadiazol-4-yl]-amide; -   Benzo[b]thiophene-2-carboxylic acid     [5,5-dimethyl-3-(3-trifluoromethyl-phenyl)-[1,2,4]oxadiazol-4-yl]-amide; -   Benzo[b]thiophene-2-carboxylic acid     [5,5-dimethyl-3-(4-trifluoromethoxy-phenyl)-[1,2,4]oxadiazol-4-yl]-amide; -   2-Benzyloxy-N-[3-(2,4-dimethoxy-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-acetamide; -   1-Benzoyl-3-[3-(3,5-dimethyl-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-urea; -   1-[3-(3,5-Dimethyl-phenyl)-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl]-3-phenyl-urea; -   1-[3-(2,4-Dimethoxy-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-3-phenyl-urea; -   N-(5,5-Dimethyl-3-phenyl-[1,2,4]oxadiazol-4-yl)-4-ethyl-benzamide; -   2-Benzyloxy-N-[3-(4-chloro-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-acetamide; -   N-(5-Ethyl-5-methyl-3-phenyl-[1,2,4]oxadiazol-4-yl)-benzamide; -   N-[3-(3,5-Dimethyl-phenyl)-5-ethyl-5-methyl-[1,2,4]oxadiazol-4-yl]-2-phenyl-acetamide; -   N-[3-(4-Chloro-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-2-phenyl-acetamide; -   1-[5,5-Dimethyl-3-(4-trifluoromethoxy-phenyl)-[1,2,4]oxadiazol-4-yl]-3-phenyl-urea; -   4-Ethyl-N-(3-phenyl-1,8-dioxa-2,4-diaza-spiro[4.5]dec-2-en-4-yl)-benzamide; -   4-Ethyl-N-(3-phenyl-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl)-benzamide; -   N-[3-(3,5-Dimethyl-phenyl)-5-ethyl-5-methyl-[1,2,4]oxadiazol-4-yl]-succinamic     acid ethyl ester; -   N-(3-Benzo[1,3]dioxol-5-yl-5,5-dimethyl-[1,2,4]oxadiazol-4-yl)-2-phenoxy-acetamide; -   N-[3-(3,5-Dimethyl-phenyl)-5-ethyl-5-methyl-[1,2,4]oxadiazol-4-yl]-4-ethyl-benzamide; -   Benzo[b]thiophene-2-carboxylic acid     [3-(2,4-dimethoxy-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-amide; -   2-Phenyl-N-(3-phenyl-1,8-dioxa-2,4-diaza-spiro[4.5]dec-2-en-4-yl)-acetamide; -   1-Phenyl-3-(3-phenyl-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl)-urea; -   Benzo[b]thiophene-2-carboxylic acid     (5-ethyl-5-methyl-3-phenyl-[1,2,4]oxadiazol-4-yl)-amide; -   N-[3-(2,4-Dimethoxy-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-4-ethyl-benzamide; -   4-Ethyl-N-(5-ethyl-5-methyl-3-phenyl-[1,2,4]oxadiazol-4-yl)-benzamide; -   Furan-2-carboxylic acid     [3-(3,5-dimethyl-phenyl)-1,8-dioxa-2,4-diaza-spiro[4.5]dec-2-en-4-yl]-amide; -   Benzo[b]thiophene-2-carboxylic acid     (3-benzo[1,3]dioxol-5-yl-5,5-dimethyl-[1,2,4]oxadiazol-4-yl)-amide; -   N-[3-(3,5-Dimethyl-phenyl)-5-ethyl-5-methyl-[1,2,4]oxadiazol-4-yl]-2-phenoxy-acetamide; -   N-(3-Biphenyl-4-yl-5,5-dimethyl-[1,2,4]oxadiazol-4-yl)-4-ethyl-benzamide; -   N-[3-(2-Methoxy-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-succinamic     acid ethyl ester; -   N-(3-Benzo[1,3]dioxol-5-yl-5,5-dimethyl-[1,2,4]oxadiazol-4-yl)-2-benzyloxy-acetamide; -   N-(5-Ethyl-5-methyl-3-phenyl-[1,2,4]oxadiazol-4-yl)-2-phenyl-acetamide; -   N-[3-(2-Methoxy-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-benzamide; -   N-[5,5-Dimethyl-3-(3-trifluoromethyl-phenyl)-[1,2,4]oxadiazol-4-yl]-4-ethyl-benzamide; -   Furan-2-carboxylic acid     (3-benzo[1,3]dioxol-5-yl-5,5-dimethyl-[1,2,4]oxadiazol-4-yl)-amide; -   Benzo[b]thiophene-2-carboxylic acid     (3-phenyl-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl)-amide; -   N-[3-(4-Chloro-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-benzamide; -   Benzo[b]thiophene-2-carboxylic acid     [3-(3,5-dimethyl-phenyl)-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl]-amide; -   N-[5,5-Dimethyl-3-(3-trifluoromethyl-phenyl)-[1,2,4]oxadiazol-4-yl]-succinamic     acid ethyl ester; -   2-Benzyloxy-N-(5-ethyl-5-methyl-3-phenyl-[1,2,4]oxadiazol-4-yl)-acetamide; -   2-Benzyloxy-N-(3-phenyl-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl)-acetamide; -   N-(3-Benzo[1,3]dioxol-5-yl-5,5-dimethyl-[1,2,4]oxadiazol-4-yl)-benzamide; -   N-[3-(2-Methoxy-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-2-phenyl-acetamide; -   2-Phenoxy-N-(3-phenyl-1-oxa-2,4-diaza-spiro[4,4]non-2-en-4-yl)-acetamide; -   2-Ethyl-3-methoxy-N-(3-phenyl-1,8-dioxa-2,4-diaza-spiro[4.5]dec-2-en-4-yl)-benzamide; -   N-[5,5-Dimethyl-3-(4-trifluoromethoxy-phenyl)-[1,2,4]oxadiazol-4-yl]-2-phenyl-acetamide; -   Benzo[b]thiophene-2-carboxylic acid     [3-(3,5-dimethyl-phenyl)-5-ethyl-5-methyl-[1,2,4]oxadiazol-4-yl]-amide; -   N-[3-(4-Chloro-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-2-phenoxy-acetamide; -   N-[5,5-Dimethyl-3-(3-trifluoromethyl-phenyl)-[1,2,4]oxadiazol-4-yl]-2-phenoxy-acetamide; -   N-[3-(4-Chloro-phenyl)-5,5-dimethyl-[1,2,4]oxadiazol-4-yl]-succinamic     acid ethyl ester; -   N-[3-(3,5-Dimethyl-phenyl)-5-ethyl-5-methyl-[1,2,4]oxadiazol-4-yl]-4-ethyl-2-fluoro-benzamide; -   4-Ethyl-2-fluoro-N-(3-phenyl-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl)-benzamide; -   N-[3-(3,5-Dimethyl-phenyl)-1-oxa-2,4-diaza-spiro[4.4]non-2-en-4-yl]-4-ethyl-2-fluoro-benzamide; -   N-(5,5-Dimethyl-3-phenyl-[1,2,4]oxadiazol-4-yl)-4-ethyl-2-fluoro-benzamide; -   5-Ethyl-2,3-dihydro-benzo[1,4]dioxine-6-carboxylic acid     (5,5-dimethyl-3-phenyl-[1,2,4]oxadiazol-4-yl)-amide, and -   5-Ethyl-2,3-dihydro-benzo[1,4]dioxine-6-carboxylic acid     [3-(3,5-dimethyl-phenyl)-5-ethyl-5-methyl-[1,2,4]oxadiazol-4-yl]-amide.

In another embodiment, the activating ligand is a compound having Formula IX or X:

-   -   wherein R¹, R², R³, and R⁴ are each independently:         -   a) H, (C₁-C₆)alkyl; (C₁-C₆)haloalkyl; (C₁-C₆)cyanoalkyl;             (C₁-C₆)hydroxyalkyl; (C₁-C₄)alkoxy(C₁-C₆)alkyl;             (C₂-C₆)alkenyl optionally substituted with halo, cyano,             hydroxyl, or (C₁-C₄)alkyl; (C₂-C₆)alkynyl optionally             substituted with halo, cyano, hydroxyl, or (C₁-C₄)alkyl;             (C₃-C₅)cycloalkyl optionally substituted with halo, cyano,             hydroxyl, or (C₁-C₄)alkyl, oxiranyl optionally substituted             with halo, cyano, or (C₁-C₄)alkyl; or         -   b) unsubstituted or substituted benzyl wherein the             substituents are independently 1 to 5 H, halo, nitro, cyano,             hydroxyl, (C₁-C₆)alkyl, or (C₁-C₆)alkoxy; and         -   R⁵ is H; OH; F, Cl; or (C₁-C₆)alkoxy.

In another embodiment, the activating ligand is a compound selected from the group consisting of 20-hydroxyecdysone-2-methyl ether; 20-hydroxyecdysone-3-methyl ether; 20-hydroxyecdysone-14-methyl ether; 20-hydroxyecdysone-2,22-dimethyl ether; 20-hydroxyecdysone-3,22-dimethyl ether, 20-hydroxyecdysone-14,22-dimethyl ether; 20-hydroxyecdysone-22,25-dimethyl ether; 20-hydroxyecdysone-2,3,14,22-tetramethyl ether; 20-hydroxyecdysone-22-n-propyl ether; 20-hydroxyecdysone-22-n-butyl ether; 20-hydroxyecdysone-22-allyl ether, 20-hydroxyecdysone-22-benzyl ether; 20-hydroxyecdysone-22-(28R,S)-2′-ethyloxiranyl ether; ponasterone A-2-methyl ether; ponasterone A-14-methyl ether; ponasterone A-22-methyl ether; ponasterone A-2,22-dimethyl ether; ponasterone A-3,22-dimethyl ether, ponasterone A-14,22-dimethyl ether; dacryhainansterone-22-methyl ether; 25,26-didehydroponasterone A (iso-stachysterone C (Δ25(26))); shidasterone (stachysterone D), stachysterone C; 22-deoxy-20-hydroxyecdysone (taxisterone); ponasterone A; polyporusterone B; 22-dehydro-20-hydroxyecdysone; 20-hydroxyecdysone; pterosterone; (25R)-inokosterone, (25S)-inokosterone; pinnatasterone; 25-fluoroponasterone A; 24(28)-dehydromakisterone A; 24-epi-makisterone A; makisterone A; 20-hydroxyecdysone-22-methyl ether; 20-hydroxyecdysone-25-methyl ether; abutasterone; 22,23-di-epi-geradiasterone; 20,26-dihydroxyecdysone (podecdysone C), 24-epi-abutasterone; geradiasterone; 29-norcyasterone; ajugasterone B; 24(28)[Z]-dehydroamarasterone B; amarasterone A; makisterone C; rapisterone C; 20-hydroxyecdysone-22,25-dimethyl ether, 20-hydroxyecdysone-22-ethyl ether; carthamosterone; 24(25)-dehydroprecyasterone; leuzeasterone; cyasterone; 20-hydroxyecdysone-22-allyl ether, 24(28)[Z]-dehydro-29-hydroxymakisterone C; 20-hydroxyecdysone-22-acetate; viticosterone E (20-hydroxyecdysone 25-acetate); 20-hydroxyecdysone-22-n-propyl ether; 24-hydroxycyasterone; ponasterone A 22-hemisuccinate; 22-acetoacetyl-20-hydroxyecdysone; canescensterone; 20-hydroxyecdysone-22-hemisuccinate; inokosterone-26-hemisuccinate; 20-hydroxyecdysone-22-benzoate; 20-hydroxyecdysone-22-β-D-glucopyranoside; 20-hydroxyecdysone-25-β-D-glucopyranoside; sileneoside A (20-hydroxyecdysone-22α-galactoside); 3-deoxy-1β,20-dihydroxyecdysone (3-deoxyintegristerone A); 2-deoxyintegristerone A; 1-epi-integristerone A; integristerone A; sileneoside C (integristerone A 22α-galactoside); 2,22-dideoxy-20-hydroxyecdysone; 2-deoxy-20-hydroxyecdysone; 2-deoxy-20-hydroxyecdysone-3-acetate; 2-deoxy-20,26-dihydroxyecdysone; 2-deoxy-20-hydroxyecdysone-22-acetate; 2-deoxy-20-hydroxyecdysone-3,22-diacetate, 2-deoxy-20-hydroxyecdysone-22-benzoate; ponasterone A 2-hemisuccinate; 20-hydroxyecdysone-2-acetate; 20-hydroxyecdysone-2-hemisuccinate; 20-hydroxyecdysone-2-β-D-glucopyranoside; 2-dansyl-20-hydroxyecdysone; 20-hydroxyecdysone-2,22-dimethyl ether; ponasterone A 3β-D-xylopyranoside (limnantheoside B); 20-hydroxyecdysone-3-methyl ether; 20-hydroxyecdysone-3-acetate; 20-hydroxyecdysone-3β-D-xylopyranoside (limnantheoside A); 20-hydroxyecdysone-3-β-D-glucopyranoside; sileneoside D (20-hydroxyecdysone-3α-galactoside); 20-hydroxyecdysone 3β-D-glucopyranosyl-[1-3]-β-D-xylopyranoside (limnantheoside C); cyasterone-3-acetate; 2-dehydro-3-epi-20-hydroxyecdysone; 3-epi-20-hydroxyecdysone (coronatasterone); rapisterone D; 3-dehydro-20-hydroxyecdysone; 5β-hydroxy-25,26-didehydroponasterone A; 5β-hydroxystachysterone C; 25-deoxypolypodine B; polypodine B; 25-fluoropolypodine B; 5β-hydroxyabutasterone; 26-hydroxypolypodine B; 29-norsengosterone, sengosterone; 6β-hydroxy-20-hydroxyecdysone; 6α-hydroxy-20-hydroxyecdysone; 20-hydroxyecdysone-6-oxime; ponasterone A 6-carboxymethyloxime; 20-hydroxyecdysone-6-carboxymethyloxime; ajugasterone C; rapisterone B; muristerone A; atrotosterone B; atrotosterone A, turkesterone-2-acetate; punisterone (rhapontisterone); turkesterone; atrotosterone C; 25-hydroxyatrotosterone B; 25-hydroxyatrotosterone A; paxillosterone; turkesterone-2,22-diacetate; turkesterone-22-acetate; turkesterone-11α-acetate; turkesterone-2,11α-diacetate; turkesterone-11α-propionate; turkesterone-11α-butanoate; turkesterone-11α-hexanoate; turkesterone-11α-decanoate; turkesterone-11α-laurate; turkesterone-11α-myristate; turkesterone-11α-arachidate, 22-dehydro-12β-hydroxynorsengosterone; 22-dehydro-12β-hydroxycyasterone; 22-dehydro-12β-hydroxysengosterone; 14-deoxy(14α-H)-20-hydroxyecdysone; 20-hydroxyecdysone-14-methyl ether; 14α-perhydroxy-20-hydroxyecdysone; 20-hydroxyecdysone-2,3,14,22-tetramethyl ether; (20S)-22-deoxy-20,21-dihydroxyecdysone; 22,25-dideoxyecdysone; (22S)-20-(2,2′-dimethylfuranyl)ecdysone, (22R)-20-(2,2′-dimethylfuranyl)ecdysone; 22-deoxyecdysone; 25-deoxyecdysone; 22-dehydroecdysone; ecdysone; 22-epi-ecdysone; 24-methylecdysone (20-deoxymakisterone A); ecdysone-22-hemisuccinate; 25-deoxyecdysone-22-β-D-glucopyranoside; ecdysone-22-myristate; 22-dehydro-20-iso-ecdysone; 20-iso-ecdysone; 20-iso-22-epi-ecdysone; 2-deoxyecdysone; sileneoside E (2-deoxyecdysone 3β-glucoside, blechnoside A); 2-deoxyecdysone-22-acetate; 2-deoxyecdysone-3,22-diacetate; 2-deoxyecdysone-22-β-D-glucopyranoside; 2-deoxyecdysone 25-β-D-glucopyranoside; 2-deoxy-21-hydroxyecdysone; 3-epi-22-iso-ecdysone; 3-dehydro-2-deoxyecdysone (silenosterone); 3-dehydroecdysone; 3-dehydro-2-deoxyecdysone-22-acetate; ecdysone-6-carboxymethyloxime; ecdysone-2,3-acetonide; 14-epi-20-hydroxyecdysone-2,3-acetonide; 20-hydroxyecdysone-2,3-acetonide; 20-hydroxyecdysone-20,22-acetonide; 14-epi-20-hydroxyecdysone-2,3,20,22-diacetonide; paxillosterone-20,22-p-hydroxybenzylidene acetal; poststerone; (20R)-dihydropoststerone; (20S)dihydropoststerone; poststerone-20-dansylhydrazine; (20S)-dihydropoststerone-2,3,20-tribenzoate; (20R)-dihydropoststerone-2,3,20-tribenzoate; (20R)dihydropoststerone-2,3-acetonide; (2(20S)dihydropoststerone-2,3-acetonide; (5α-H)-dihydrorubrosterone; 2,14,22,25-tetradeoxy-5α-ecdysone; 5α-ketodiol, bombycosterol, 2α,3α,22S,25-tetrahydroxy-5α-cholestan-6-one; (5α-H)-2-deoxy-21-hydroxyecdysone, castasterone; 24-epi-castasterone; (5α␣-H)-2-deoxyintegristerone A; (5α-H)-22-deoxyintegristerone A; (5α-H)-20-hydroxyecdysone; 24,25-didehydrodacryhaninansterone; 25,26-didehydrodacryhainansterone; 5-deoxykaladasterone (dacryhainansterone); (14α-H)-14-deoxy-25-hydroxydacryhainansterone; 25-hydroxydacryhainansterone; rubrosterone; (5β-H)-dihydrorubrosterone; dihydrorubrosterone-17β-acetate, sidisterone; 20-hydroxyecdysone-2,3,22-triacetate, 14-deoxy(14β-H)-20-hydroxyecdysone; 14-epi-20-hydroxyecdysone; 9α,20-dihydroxyecdysone; malacosterone, 2-deoxypolypodine B-3-β-D-glucopyranoside; ajugalactone; cheilanthone B; 2β,3β,6α-trihydroxy-5β-cholestane; 2β,3β,6β-trihydroxy-5β-cholestane; 14-dehydroshidasterone; stachysterone B; 2β,3β,9α,20R,22R,25-hexahydroxy-5β-cholest-7,14-dien-6-one; kaladasterone; (14β-H)-14-deoxy-25-hydroxydacryhainansterone; 4-dehydro-20-hydroxyecdysone; 14-methyl-12-en-shidasterone; 14-methyl-12-en-15,20-dihydroxyecdysone; podecdysone B; 2β,3β,20R,22R-tetrahydroxy-25-fluoro-5β-cholest-8,14-dien-6-one (25-fluoropodecdysone B); calonysterone; 14-deoxy-14,18-cyclo-20-hydroxyecdysone; 9α,14α-epoxy-20-hydroxyecdysone; 9βα,14β-epoxy-20-hydroxyecdysone; 9α,14α-epoxy-20-hydroxyecdysone 2,3,20,22-diacetonide; 28-homobrassinolide; and iso-homobrassinolide.

The disclosure of all patents, patent applications, and publications cited herein are incorporated by reference in their entireties.

The following examples are illustrative, but not limiting, of the methods of the present invention. Other suitable modifications and adaptations of the variety of conditions and parameters normally encountered in medical treatment and gene expression systems and which are obvious to those skilled in the art are within the spirit and scope of the invention.

Pharmaceutical Compositions

In certain embodiments, polynucleotides and polypeptides of the invention can be administered as part of a medicament or pharmaceutical composition. Medicaments and pharmaceutical compositions of the invention comprise one or more pharmaceutically acceptable carriers, diluents, excipients or additives.

The term “excipient” as used herein is typically an inert substance added to a composition to facilitate processing, handling, administration, et cetera of a pharmaceutically acceptable composition. Useful excipients include, but are not limited to, adjuvants, anti-adherents, binders, carriers, disintegrants, fillers, flavors, colors, diluents, lubricants, glidants, preservatives, sorbents, solvents, surfactants, and sweeteners.

A few examples of pharmaceutically acceptable carriers, diluents, excipients and additives include, without limitation, water, saline, Ringer's solution, dextrose solution, buffers (such as phosphates (e.g., calcium phosphates such as tricalcium phosphate or calcium hydrogen phosphate)), citrate, succinate, acetic acid, and other organic acids or their salts), antioxidants, proteins and other high molecular weight molecules (such as serum albumin, gelatin, or immunoglobulins), hydrophilic polymers (such as polyvinylpyrrolidone), amino acids (such as glycine, glutamic acid, aspartic acid, and arginine), saccharides (for example monosaccharides, disaccharides, lactose, sucrose, mannitol, sorbitol, other carbohydrates and sugar-alcohols, cellulose or its derivatives, glucose, mannose, and dextrins), chelating agents (such as EDTA); sugar alcohols (such as mannitol or sorbitol), counterions (such as sodium), surfactants (such as polysorbates, poloxamers, or polyethylene glycol (PEG)), and binders (such as starch paste (e.g., maize starch, wheat starch, rice starch, potato starch)), gelatin, tragacanth, methyl cellulose, hydroxypropylmethylcellulose, sodium carboxymethylcellulose, and/or polyvinyl pyrrolidone).

Pharmaceutically acceptable carriers, diluents, excipients and additives may include: disintegrating agents such as the above-mentioned starches as well as compounds such as carboxymethyl-starch, cross-linked polyvinyl pyrrolidone, agar, or alginic acid or a salt thereof, such as sodium alginate; and, flow-regulating agents and lubricants, for example, silica, talc, stearic acid or salts thereof such as magnesium stearate or calcium stearate, and/or polyethylene glycol. In one embodiment, dragee cores are provided with suitable coatings which, if desired, are resistant to gastric juices. For this purpose, concentrated saccharide solutions may be used, which may optionally contain gum arabic, talc, polyvinyl pyrrolidone, polyethylene glycol and/or titanium dioxide, lacquer solutions and suitable organic solvents or solvent mixtures. In order to produce coatings resistant to gastric juices, solutions of suitable cellulose preparations such as acetyl cellulose phthalate or hydroxypropylmethyl-cellulose phthalate, are used. Dye stuffs or pigments may be added to the tablets or dragee coatings, for example, for identification or in order to characterize combinations of active compound doses.

Pharmaceutical preparations which can be used orally include push-fit capsules made of gelatin, as well as soft, sealed capsules made of gelatin and a plasticizer such as glycerol or sorbitol. The push-fit capsules can contain the active compounds in the form of granules or nanoparticles which may optionally be mixed with fillers such as lactose, binders such as starches, and/or lubricants such as talc or magnesium stearate and, optionally, stabilizers. In one embodiment, the is dissolved or suspended in suitable liquids, such as fatty oils, or liquid paraffin, optionally with stabilizers.

Fatty oils may comprise mono-, di- or triglycerides. Mono-, di- and triglycerides include those that are derived from C6, C8, C10, C12, C14, C16, C18, C20 and C22 acids. Exemplary diglycerides include, in particular, diolein, dipalmitolein, and mixed caprylin-caprin diglycerides. Preferred triglycerides include vegetable oils, fish oils, animal fats, hydrogenated vegetable oils, partially hydrogenated vegetable oils, synthetic triglycerides, modified triglycerides, fractionated triglycerides, medium and long-chain triglycerides, structured triglycerides, and mixtures thereof. Exemplary triglycerides include: almond oil; babassu oil; borage oil, blackcurrant seed oil; canola oil; castor oil; coconut oil; corn oil; cottonseed oil; evening primrose oil; grapeseed oil; groundnut oil; mustard seed oil; olive oil; palm oil; palm kernel oil; peanut oil, rapeseed oil; safflower oil; sesame oil; shark liver oil; soybean oil; sunflower oil; hydrogenated castor oil; hydrogenated coconut oil; hydrogenated palm oil; hydrogenated soybean oil; hydrogenated vegetable oil, hydrogenated cottonseed and castor oil; partially hydrogenated soybean oil; partially soy and cottonseed oil; glyceryl tricaproate; glyceryl tricaprylate; glyceryl tricaprate; glyceryl triundecanoate; glyceryl trilaurate; glyceryl trioleate; glyceryl trilinoleate; glyceryl trilinolenate, glyceryl tricaprylate/caprate; glyceryl tricaprylate/caprate/laurate; glyceryl tricaprylate/caprate/linoleate; and glyceryl tricaprylate/caprate/stearate.

In one embodiment, the triglyceride is the medium chain triglyceride available under the trade name LABRAFAC CC. Other triglycerides include neutral oils, e.g., neutral plant oils, in particular fractionated coconut oils such as known and commercially available under the trade name MIGLYOL, including the products: MIGLYOL 810; MIGLYOL 812; MIGLYOL 818; and CAPTEX 355. Other triglycerides are caprylic-capric acid triglycerides such as known and commercially available under the trade name MYRITOL, including the product MYRITOL 813. Further triglycerides of this class are CAPMUL MCT, CAPTEX 200, CAPTEX 300, CAPTEX 800, NEOBEE M5 and MAZOL 1400.

Pharmaceutical compositions comprising triglycerides may further comprise lipophilic and/or hydrophilic surfactants which may form clear solutions upon dissolution with an aqueous solvent. One such surfactant is tocopheryl polyethylene glycol 1000 succinate (vitamin E TPGS). Examples of such compositions are described in U.S. Pat. No. 6,267,985.

In another embodiment, the pharmaceutically acceptable carrier comprises LABRASOL (Gattefosse SA), which is PEG-8 caprylic/capric glycerides. In another embodiment, the pharmaceutically acceptable carrier comprises PL90G, vitamin E TPGS, and Miglyol 812N.

Pharmaceutical compositions can be administered in any suitable manner as determined by those skilled in the art, such as, but without limitation, by oral, rectal, vaginal, topical (including dermal, buccal and sublingual), parenteral, intravenous, intraperitoneal, intramuscular, intratumoral, intraarticular, subcutaneous, intranasal, inhalation, intradermal, intrathecal, epidural, and by nasogastric routes.

Methods and compositions for preparation, formulation, and delivery of pharmaceutically acceptable compositions and medicaments are well-known and routinely practiced by those skilled in the art. A few examples of textbooks and manuals providing information and instruction on such methods and compositions include: Rowe et al. (Editor), “Handbook of Pharmaceutical Excipients,” Pharmaceutical Press, 6^(th) Ed. (August 2009); University of the Sciences in Philadelphia (Editor), “Remington: The Science and Practice of Pharmacy” Lippincott Williams & Wilkins, 21^(st) Ed. (2005); “Physicians' Desk Reference 2011,” PDR Network (2010); “Physicians' Desk Reference 2012,” PDR Network (2011); O'Neil, “The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals,” 14^(th) Ed. (2006); Allen et al. (Editor) “Ansel's Pharmaceutical Dosage Forms and Drug Delivery Systems,” Lippincott Williams & Wilkins; 9^(th) Ed. (2011); and, Ash et al. (Editor), “Handbook of Pharmaceutical Additives, Third Edition,” Synapse Information Resources, Inc.; 3^(rd) Ed. (2007).

Protocols for general molecular biology methods can be found in: Methods in Molecular Biology, series editor J M Walker, Humana Press, New York.

Embodiments of the invention comprise any amino acid substituted form of PE as indicated by, or represented in, Table 13. Embodiments of the invention further comprise any amino acid substituted form of PE which may comprise any combination of amino acid substitutions indicated by, or represented in, Table 13.

Embodiments of the invention also comprise variants, derivatives, or biologically active fragments of any amino acid substituted form of PE as indicated by, or represented in, Table 13, wherein said variant, derivative, or biologically active fragment of PE is at least 80% identical, at least 85% identical, at least 90% identical, at least 95% identical, at least 97% identical, at least 98% identical, at least 99% identical, or is at least 100% identical to an amino acid substituted form of PE, or a fragment thereof, as indicated by, or represented in, Table 13. For example, embodiments of the invention comprise variants, derivatives, or biologically active fragments of any amino acid substituted form of PE as indicated by, or represented in, Table 13, wherein said variant, derivative, or biologically active fragment of PE is at least 80% identical, at least 85% identical, at least 90% identical, at least 95% identical, at least 97% identical, at least 98% identical, at least 99% identical, or is at least 100% identical to PE constructs, or fragments thereof, as represented by pIEX02-003 through pIEX02-248 in Table 13 (such as, for example, as shown in SEQ ID NO:177 (pIEX02-228), SEQ ID NO:178 (pIEX02-244), and SEQ ID NO:179 (pIEX02-246)).

Embodiments of the invention include methods of making, methods of using, methods of treatment using, medicaments comprising, pharmaceutically acceptable compositions comprising, therapeutically useful compositions comprising, and kits comprising any of the amino acid substituted forms of PE referenced, or otherwise described or provided for, herein.

Embodiments of the invention also include (where “E” indicates “embodiment”):

-   -   E1. An isolated polypeptide having Pseudomonas exotoxin A         biological activity, wherein said polypeptide comprises an         epitope selected from the group consisting of:

a) (SEQ ID NO: 5) ISFSTRGTQ; b) (SEQ ID NO: 6) GIQNWTVER; c) (SEQ ID NO: 7) IVFGGVRAR; d) (SEQ ID NO: 8) ARSQDLDAI; e) (SEQ ID NO: 9) LPNYVPRSS; f) (SEQ ID NO: 10) IPDKEQAIS; g) (SEQ ID NO: 131) ISFSTRGTQNWTVER;  and h) (SEQ ID NO: 132) IVFGGVRARSQDLDAI

-   -   wherein one or more amino acid residues in any one or more of         said epitopes in a) through h) are substituted with a different         amino acid residue.     -   E2. An isolated polypeptide having Pseudomonas exotoxin A         biological activity, wherein said polypeptide comprises an         epitope selected from the group consisting of:         -   a) ISFSTRGTQ (SEQ ID NO:5), wherein amino acid residues at             one or more of positions 1, 6 and 9 are substituted with a             different amino acid residue;         -   b) GTQNWTVER (SEQ ID NO:6), wherein amino acid residues at             one or more of positions 3, 4 and 6 are substituted with a             different amino acid residue;         -   c) IVFGGVRAR (SEQ ID NO:7), wherein amino acid residues at             one or more of positions 1 and 6 are substituted with a             different amino acid residue;         -   d) ARSQDLDAI (SEQ ID NO:8), wherein amino acid residues at             one or more of positions 4 and 7 are substituted with a             different amino acid residue;         -   e) LRVYVPRSS (SEQ ID NO:9), wherein amino acid residues at             one or more of positions 1, 2 and 9 are substituted with a             different amino acid residue;         -   f) IPDKEQAIS (SEQ ID NO:10), wherein amino acid residues at             one or more of positions 1, 4, 6 and 7 are substituted with             a different amino acid residue;         -   g) ISFSTRGTQNWTVER (SEQ ID NO:131), wherein amino acid             residues at one or more of positions 1, 6, 9, 10 and 12 are             substituted with a different amino acid residue; and         -   h) IVFGGVRARSQDLDAI (SEQ ID NO:132), wherein amino acid             residues at one or more of positions 1, 6, 11, and 14 are             substituted with a different amino acid residue.     -   E3. The isolated polypeptide of embodiment E1 or E2, wherein         said different amino acid residue is a conservative amino acid         substitution.     -   E4. The isolated polypeptide of embodiment E3, wherein said         conservative amino acid substitution is one or more         substitutions selected from the group consisting of:         -   a) A is substituted with any one of G, I, L, S, T or V;         -   b) D is substituted with E;         -   c) I is substituted with any one of L, M or V;         -   d) K is substituted with any one of H or R;         -   e) L is substituted with any one of A, G, I, M or V;         -   f) N is substituted with any one of S, T or Q;         -   g) Q is substituted with any one of S, T or N;         -   h) R is substituted with any one of K or H;         -   i) S is substituted with any one of A, G, N, T or Q;         -   j) T is substituted with any one of A, G, N, Q or S, and         -   k) V is substituted with any one of A, G, I, L or M.     -   E5. An isolated polypeptide having Pseudomonas exotoxin A         biological activity, wherein said polypeptide comprises an         epitope selected from the group consisting of:         -   a) ISFSTRGTQ (SEQ ID NO:5), wherein amino the acid residue             at position 1 (I) is substituted with A, N, T, Q or H, or             wherein the amino acid residue at position 6 (R) is             substituted with Q, or wherein the amino acid residue at             position 9 (Q) is substituted with N or T, or wherein the             amino acid sequence ISFSTRGTQ (SEQ ID NO:5) comprises two or             more of said substitutions in any combination;         -   b) GTQNWTVER (SEQ ID NO:6), wherein the amino acid residue             at position 3 (Q) is substituted with N or T, wherein amino             the acid residue at position 4 (N) is substituted with K or             R, or wherein the amino acid residue at position 6 (T) is             substituted with K or R, or wherein the amino acid sequence             GTQNWTVER (SEQ ID NO:6) comprises two or more of said             substitutions in any combination;         -   c) IVFGGVRAR (SEQ ID NO:7), wherein amino the acid residue             at position 1 (I) is substituted with A or N, or wherein the             amino acid residue at position 6 (V) is substituted with D,             M, or N, or wherein the amino acid sequence IVFGGVRAR (SEQ             ID NO:7) comprises substitutions at both positions in any             combination of amino acid residues A or N at position 1 (I)             and D, M, or N at position 6 (V);         -   d) ARSQDLDAI (SEQ ID NO:8), wherein amino the acid residue             at position 4 (Q) is substituted with K or R, or wherein the             amino acid residue at position 7 (D) is substituted with K             or R, or wherein the amino acid sequence ARSQDLDAI (SEQ ID             NO:8) comprises substitutions with K or R in any combination             at both positions 4 (Q) and 7 (D);         -   e) LRVYVPRSS (SEQ ID NO:9), wherein amino the acid residue             at position 1 (L) is substituted with A, or wherein the             amino acid residue at position 2 (R) is substituted with D,             S or A, or wherein the amino acid residue at position 9 (S)             is substituted with D, E, N, K, P or T, or wherein the amino             acid sequence LRVYVPRSS (SEQ ID NO:9) comprises two or more             of said substitutions in any combination;         -   f) IPDKEQAIS (SEQ ID NO:10), wherein amino acid residues at             one or more of positions 1, 4, 6 and 7 are substituted with             a different amino acid residue, wherein amino the acid             residue at position 1 (I) is substituted with A, N, T, Q or             H, or wherein the amino acid residue at position 4 (K) is             substituted with T, or wherein the amino acid residue at             position 6 (Q) is substituted with D, or wherein the amino             acid residue at position 7 (A) is substituted with D, or             wherein the amino acid sequence IPDKEQAIS (SEQ ID NO:10)             comprises two or more of said substitutions in any             combination;         -   g) ISFSTRGTQNWTVER (SEQ ID NO:131), wherein amino acid             residues at one or more of positions 1, 6, 9, 10 and 12 are             substituted with a different amino acid residues wherein             amino the acid residue at position 1 (I) is substituted with             A, N, T, Q or H, or wherein the amino acid residue at             position 6 (R) is substituted with Q, or wherein the amino             acid residue at position 9 (Q) is substituted with N or T,             or wherein amino the acid residue at position 10 (N) is             substituted with K or R, or wherein the amino acid residue             at position 12 (T) is substituted with K or R, or wherein             the amino acid sequence ISFSTRGTQNWTVER (SEQ ID NO:131)             comprises two or more of said substitutions in any             combination, and         -   h) IVFGGVRARSQDLDAI (SEQ ID NO:132), wherein amino the acid             residue at position 1 (I) is substituted with A or N, or             wherein the amino acid residue at position 6 (V) is             substituted with D, M, or N, wherein amino the acid residue             at position 11 (Q) is substituted with K or R, or wherein             the amino acid residue at position 14 (D) is substituted             with K or R, or wherein the amino acid sequence             IVFGGVRARSQDLDAI (SEQ ID NO:132) comprises two or more of             said substitutions in any combination.     -   E6. An isolated polypeptide having Pseudomonas exotoxin A         biological activity, wherein said polypeptide comprises an         epitope selected from the group consisting of:         -   a) I at position 141 is a different amino acid;         -   b) R at position 146 is a different amino acid;         -   c) Q at position 149 is a different amino acid;         -   d) N at position 150 is a different amino acid;         -   e) T at position 152 is a different amino acid,         -   f) I at position 184 is a different amino acid;         -   g) V at position 189 is a different amino acid;         -   h) Q at position 194 is a different amino acid;         -   i) D at position 197 is a different amino acid;         -   j) L at position 233 is a different amino acid,         -   k) R at position 234 is a different amino acid;         -   l) S at position 241 is a different amino acid;         -   m) I at position 321 is a different amino acid;         -   n) K at position 324 is a different amino acid;         -   o) Q at position 326 is a different amino acid;         -   p) A at position 327 is a different amino acid;         -   q) any combination of one or more of a) through p),     -   wherein the amino acid numbering corresponds to SEQ ID NO:1.     -   E7. An isolated polypeptide comprising an amino acid sequence         identical to SEQ ID NO:1, except for one or more amino acid         substitutions selected from the group consisting of:         -   a) I at position 141 is substituted with a conservative             amino acid substitution;         -   b) R at position 146 is substituted with a conservative             amino acid substitution;         -   c) Q at position 149 is substituted with a conservative             amino acid substitution;         -   d) N at position 150 is substituted with a conservative             amino acid substitution;         -   e) T at position 152 is substituted with a conservative             amino acid substitution,         -   f) I at position 184 is substituted with a conservative             amino acid substitution;         -   g) V at position 189 is substituted with a conservative             amino acid substitution;         -   h) Q at position 194 is substituted with a conservative             amino acid substitution d;         -   i) D at position 197 is substituted with a conservative             amino acid substitution;         -   j) L at position 233 is substituted with a conservative             amino acid substitution;         -   k) R at position 234 is substituted with a conservative             amino acid substitution;         -   l) S at position 241 is substituted with a conservative             amino acid substitution;         -   m) I at position 321 is substituted with a conservative             amino acid substitution;         -   n) K at position 324 is substituted with a conservative             amino acid substitution;         -   o) Q at position 326 is substituted with a conservative             amino acid substitution;         -   p) A at position 327 is substituted with a conservative             amino acid substitution;         -   q) any combination of one or more of a) through p),     -   wherein the amino acid numbering corresponds to SEQ ID NO:1.     -   E8. The isolated polypeptide of embodiment E7, wherein said         conservative amino acid substitution is one or more         substitutions selected from the group consisting of:         -   a) A is substituted with any one of G, I, L, S, T or V;         -   b) D is substituted with E;         -   c) I is substituted with any one of L, M or V,         -   d) K is substituted with any one of H or R;         -   e) L is substituted with any one of A, G, I, M or V;         -   f) N is substituted with any one of S, T or Q;         -   g) Q is substituted with any one of S, T or N;         -   h) R is substituted with any one of K or H;         -   i) S is substituted with any one of A, G, N, T or Q;         -   j) T is substituted with any one of A, G, N, Q or S; and         -   k) V is substituted with any one of A, G, I, L or M.     -   E9. An isolated polypeptide comprising an amino acid sequence         identical to SEQ ID NO:1, except for one or more amino acid         substitutions selected from the group consisting of:

a) I at position 141 is A; b) I at position 141 is N; c) I at position 141 is T; d) I at position 141 is Q; e) I at position 141 is H; f) R at position 146 is Q; g) Q at position 149 is N; h) Q at position 149 is T; i) N at position 150 is R; j) N at position 150 is K; k) T at position 152 is R; l) T at position 152 is K; m) I at position 184 is A; n) I at position 184 is N; o) V at position 189 is D; p) V at position 189 is M; q) V at position 189 is N; r) Q at position 194 is R; s) Q at position 194 is K; t) D at position 197 is R; u) D at position 197 is K; v) L at position 233 is A; w) R at position 234 is D; x) R at position 234 is S; y) R at position 234 is A; z) S at position 241 is D; ab) S at position 241 is E; ac) S at position 241 is N; ad) S at position 241 is K; ae) S at position 241 is P; af) S at position 241 is T; ag) I at position 321 is A; ah) I at position 321 is N; ai) I at position 321 is T; ak) I at position 321 is Q; al) I at position 321 is H; am) K at position 324 is T; an) Q at position 326 is D; ao) A at position 327 is D; ap) any combination of one or more of a) through ao),

-   -   wherein the amino acid numbering corresponds to SEQ ID NO:1.     -   E10. The polypeptide in any one of embodiments E1 to E9,         comprising a number of amino acid substitutions selected from         the group consisting of:

a) 1 amino acid substitution; b) 2 amino acid substitutions; c) 3 amino acid substitutions; d) 4 amino acid substitutions; e) 5 amino acid substitutions; f) 6 amino acid substitutions; g) 7 amino acid substitutions; h) 8 amino acid substitutions; i) 9 amino acid substitutions; j) 10 amino acid substitutions; k) 11 amino acid substitutions; l) 12 amino acid substitutions; m) 13 amino acid substitutions; n) 14 amino acid substitutions; o) 15 amino acid substitutions; and p) 16 amino acid substitutions.

-   -   E11. The polypeptide of embodiment E9, comprising amino acid         substitutions present at each of amino acid positions 141, 146,         149, 150, 152, 184, 189, 194, 197, 233, 234, 241, 321, 324, 326         and 327.     -   E12. The polypeptide of any one of embodiments E1 to E11,         wherein said polypeptide comprises the amino acid sequence in         SEQ ID NO:1, except for amino acid substitutions indicated in         embodiments E1 to E11.     -   E13. The polypeptide in any one of embodiments E1 to E11,         wherein said polypeptide is a variant or fragment of a         Pseudomonas exotoxin A polypeptide.     -   E14. The polypeptide of embodiment E13, wherein said variant or         fragment comprises a number of epitopes selected from the group         consisting of:         -   a) at least one epitope;         -   b) at least two epitopes;         -   c) at least three epitopes;         -   d) at least four epitopes;         -   e) at least five epitopes; and         -   f) at least six epitopes.     -   E15. The polypeptide of embodiment E14, wherein said polypeptide         comprises a contiguous number of amino acids selected from the         group consisting of:         -   a) at least 20 contiguous amino acids,         -   b) at least 30 contiguous amino acids;         -   c) at least 40 contiguous amino acids;         -   d) at least 50 contiguous amino acids;         -   e) at least 60 contiguous amino acids,         -   f) at least 70 contiguous amino acids.         -   g) at least 80 contiguous amino acids;         -   h) at least 90 contiguous amino acids;         -   i) at least 100 contiguous amino acids;         -   j) at least 125 contiguous amino acids,         -   k) at least 150 contiguous amino acids;         -   l) at least 175 contiguous amino acids,         -   m) at least 200 contiguous amino acids;         -   n) at least 225 contiguous amino acids,         -   o) at least 250 contiguous amino acids;         -   p) at least 275 contiguous amino acids;         -   q) at least 300 contiguous amino acids;         -   r) at least 325 contiguous amino acids; and         -   s) at least 350 contiguous amino acids.     -   E16. An isolated polypeptide comprising a Pseudomonas exotoxin A         (PE-A) cytotoxic domain (Domain III), wherein the cytotoxic         domain comprises one or more amino acid substitutions which         prevent or reduce host immunogenic responses compared to the         same polypeptide without said one or more amino acid         substitutions.     -   E17. The polypeptide of embodiment E16, wherein said one or more         amino acid substitutions are introduced into a cytotoxic domain         sequence selected from the group consisting of:         -   (a) amino acid residues Phe-134 to Lys-347 of SEQ ID NO:1;         -   (b) amino acid residues Phe-134 to Lys-347 of SEQ ID NO:4;         -   (c) amino acid residues Phe-400 to Lys-613 of SEQ ID NO:133;             and         -   (d) amino acid residues Phe-400 to Lys-613 of SEQ ID NO:134.     -   E18. The polypeptide of embodiment E17, wherein the last five         amino acids in said cytotoxic domain are replaced with an amino         acid sequence selected from the group consisting of:

(i) (SEQ ID NO: 136) Arg-Glu-Asp-Leu;  and (ii) (SEQ ID NO: 137) Lys-Asp-Glu-Leu.

-   -   E19. The polypeptide in any one of embodiments E16 to E18,         wherein said polypeptide further comprises one or more PE-A         domains selected from the group consisting of:         -   (a) a cytosolic translocation domain (Domain II);         -   (b) a carboxy-terminal portion of Domain IB;         -   (c) an amino-terminal portion of Domain IB; and         -   (d) a complete Domain IB.     -   wherein one or more of said domains has been modified with amino         acid substitutions, as described herein, to reduce or eliminate         immunogenicity.     -   E20. The polypeptide of embodiment E19, wherein said cytosolic         translocation domain (Domain II) comprises an amino acid         sequence selected from the group consisting of:         -   (a) amino acids Gly-3 to Ser-114 of SEQ ID NO:1; and         -   (b) amino acids Gly-3 to Asn-114 of SEQ ID NO:4.     -   E21. The polypeptide of embodiment E19, wherein said         carboxy-terminal portion of Domain IB comprises the amino acid         sequence of Gly-115 to Glu-133 of SEQ ID NO:1 or wherein said         amino-terminal portion of Domain IB comprises the amino acid         sequence of Ala-365 to Ala-380 of SEQ ID NO:133.     -   E22. The polypeptide of embodiment E19, wherein said complete         Domain IB comprises the amino acid sequence of Ala-365 to         Glu-399 of SEQ ID NO:133.     -   E23. The polypeptide in any one of embodiments E16 to E22,         wherein said polypeptide is a variant or fragment of a         Pseudomonas exotoxin A polypeptide.     -   E24. The polypeptide of any one of embodiments E1 to E23,         wherein said polypeptide has one or more biological activities         selected from the group consisting of:         -   a) eukaryotic cell killing activity (cell cytotoxicity);         -   b) inhibits translation elongation factor EF-2 biological             activity;         -   c) induces or catalyzes ADP-ribosylation of EF-2; and         -   d) inhibits protein synthesis.     -   E25. The polypeptide of any one of embodiments E1 to E24,         wherein said one or more amino acid substitutions prevent or         reduce host immunogenic responses compared to the same         polypeptide without the corresponding said one or more amino         acid substitutions.     -   E26. The polypeptide of any one of embodiments E1 to E24,         wherein said one or more amino acid substitutions prevent or         reduce host immunogenic responses compared to a polypeptide         comprising an amino acid sequence selected from the group         consisting of:         -   (a) SEQ ID NO:1;         -   (b) SEQ ID NO:4;         -   (c) SEQ ID NO:133; and         -   (d) SEQ ID NO:134.     -   E27. The polypeptide of any one of embodiments E1 to E26,         wherein said polypeptide is a fusion protein.     -   E28. The fusion protein of embodiment E27, wherein the         amino-terminal end of said polypeptide in any one of embodiments         E1 to E26 is fused to the carboxyl-terminal end of a different         polypeptide.     -   E29. The fusion protein of embodiment E27, wherein the         carboxyl-terminal end of said polypeptide in any one of         embodiments E1 to E26 is fused to the amino-terminal end of a         different polypeptide.     -   E30. The fusion protein in embodiment E28 or E29, wherein said         different polypeptide comprises an antigen binding moiety.     -   E31. The fusion protein of embodiment E30, wherein said antigen         binding moiety is an antibody or fragment thereof.     -   E32. The fusion protein of embodiment E31, wherein said         antibody, or fragment thereof is an antibody selected from the         list in Table 1, or is a fragment thereof.     -   E33. The fusion protein of embodiment E31, wherein said         antibody, or fragment thereof, specifically binds to a         cancer-specific or tumor-specific antigen.     -   E34. The fusion protein of embodiment E33, wherein said         cancer-specific or tumor-specific antigen is a breast cancer         antigen.     -   E35. The fusion protein of embodiment E34, wherein said breast         cancer antigen is HER2.     -   E36. The fusion protein of embodiment E31, wherein said         antibody, or fragment thereof is selected from the group         consisting of:         -   a) ERTUMAXOMAB (Rexomun);         -   b) PERTUZUMAB (Omnitarg); and         -   c) TRASTUZUMAB (Herceptin).     -   E37. The fusion protein of any one of embodiments E27 to E29,         wherein said different polypeptide comprises a polypeptide         selected from the group consisting of:         -   a) Mesothelin;         -   b) CD24;         -   c) CD22;         -   d) CD25,         -   e) CD174;         -   f) TPBG;         -   g) CD56; and         -   h) C-type lectin-like molecule-1.     -   E38. An isolated polynucleotide encoding the polypeptide or         fusion protein in any one of embodiments E1 to E37.     -   E39. An expression vector comprising the polynucleotide of         embodiment E38.     -   E40. A host cell comprising the expression vector of embodiment         E39.     -   E41. A method of producing the polypeptide or fusion protein in         any one of embodiments E1 to E37, wherein said method comprises:         -   a) obtaining a host cell comprising a polynucleotide             encoding said polypeptide or fusion protein;         -   b) exposing said host cell to conditions wherein said             polypeptide or fusion protein is produced.     -   E42. A method of producing the polypeptide or fusion protein in         any one of embodiments E1 to E37, wherein said method comprises         use of an expression system comprising:         -   (A) a first polynucleotide encoding a first hybrid             polypeptide comprising:             -   (i) a first ligand binding domain; and             -   (ii) a DNA-binding domain;         -   (B) a second polynucleotide encoding a second hybrid             polypeptide comprising:             -   (i) a second ligand binding domain, and             -   (ii) a transactivation domain;         -   (C) a third polynucleotide encoding the polypeptide or             fusion protein in any one of embodiments E1 to E37, wherein             said third polynucleotide is operably associated with a             response element capable of being bound by the DNA-binding             domain of said first hybrid polypeptide;     -   wherein the first ligand binding domain and the second ligand         binding domain are capable of ligand-induced dimerization,     -   wherein expression of the polypeptide or fusion protein in any         one of embodiments E1 to E37 is modulated by a ligand which         induces dimerization of said first and said second ligand         binding domains,     -   wherein the polypeptide or fusion protein in any one of         embodiments E1 to E37 is produced by allowing said ligand to         contact said first and said second ligand binding domains.     -   E43. A single expression vector or two or more expression         vectors comprising the first, second, and third polynucleotides         of embodiment E42.     -   E44. The expression vector or expression vectors of embodiment         E43, wherein one or more of the vectors is a viral expression         vector.     -   E45. A host cell comprising the expression vector or expression         vectors of embodiments E43 or E44.     -   E46. A method of treating a disease or disorder comprising         administering to a subject in need thereof the polypeptide or         fusion protein in any one of embodiments E1 to E37, the         polynucleotide of embodiment E38, the vector of embodiment E39,         the host cell of embodiment E40, or a polypeptide or fusion         protein produced by the method of embodiment E41.     -   E47. A method of treating a disease or disorder comprising         delivering to a subject in need thereof a polypeptide or fusion         protein produced by the method of embodiment E42, wherein said         method comprises administration of the ligand to said subject.     -   E48. The method of embodiment E47, wherein the polypeptide or         fusion protein is delivered to the subject by first         administering the first, second, and third polynucleotides.     -   E49. The method of embodiment E47, wherein the polypeptide or         fusion protein is delivered to the subject by first         administering the expression vector or expression vectors of         embodiments E43 or E44.     -   E50. The method of embodiment E47, wherein said polypeptide or         fusion protein is delivered to the subject by first         administering the host cell of embodiment E45.     -   E51. A pharmaceutical composition comprising the polypeptide or         fusion protein in any one of embodiments E1 to E37, comprising         the polynucleotide of embodiment E38, comprising the expression         vector or expression vectors in any one of embodiments E39, E43         or E44, or comprising the host cell of embodiments E40 or E45,         and a pharmaceutically acceptable carrier, diluent or excipient.     -   E52. A medicament comprising the polypeptide or fusion protein         in any one of embodiments E1 to E37, comprising the         polynucleotide of embodiment E38, comprising the expression         vector or expression vectors in any one of embodiments E39, E43         or E44, or comprising the host cell of embodiments E40 or E45.     -   E53. Use of the medicament of embodiment E52, wherein said use         is for the treatment of a disease or disorder.     -   E54. Use of the medicament according to embodiment E53, wherein         the disease or disorder is cancer.     -   E55. A polypeptide having at least one Pseudomonas exotoxin A         (PE-A) biological activity, wherein said polypeptide comprises         one or more amino acid substitutions compared to a wild-type         PE-A polypeptide, wherein said one or more amino acid         substitutions is a substitution of a different amino acid at one         or more positions corresponding to amino acid residues in the         polypeptide of SEQ ID NO:1, wherein said substitution positions         are selected from the group consisting of:         -   a) isoleucine (I) at position 141;         -   b) arginine (R) at position 146;         -   c) glycine (G) at position 147;         -   d) glutamine (Q) at position 149;         -   e) asparagine (N) at position 150;         -   f) threonine (T) at position 152;         -   g) valine (V) at position 189;         -   h) arginine (R) at position 192;         -   i) glutamine (Q) at position 194;         -   j) aspartic acid (D) at position 197;         -   k) serine (S) at position 241;         -   l) isoleucine (I) at position 321; and         -   m) glutamine (Q) at position 326.     -   E56. The polypeptide of embodiment E55, wherein said one or more         amino acid substitutions is a conservative amino acid         substitution.     -   E57. The polypeptide of embodiment E55, wherein said one or more         amino acid substitutions is selected from the group consisting         of:         -   a) isoleucine (I) at position 141 is substituted with             alanine (A), threonine (T), or histidine (H);         -   b) arginine (R) at position 146 is substituted with             glutamine (Q) or alanine (A);         -   c) glycine (G) at position 147 is substituted with serine             (S);         -   d) glutamine (Q) at position 149 is substituted with             threonine (T);         -   e) asparagine (N) at position 150 is substituted with             alanine (A);         -   f) threonine (T) at position 152 is substituted with             alanine (A) or arginine (R);         -   g) valine (V) at 189 is substituted with alanine (A);         -   h) arginine (R) at position 192 is substituted with             alanine (A) or glutamine (Q);         -   i) glutamine (Q) at position 194 is substituted with             arginine (R);         -   j) aspartic acid (D) at position 197 is substituted with             lysine (K);         -   k) serine (S) at position 241 is substituted with threonine             (T), asparagine (N), lysine (K), or proline (P);         -   l) isoleucine (I) at position 321 is substituted with             alanine (A), asparagine (N), histidine (H), threonine (T),             or glutamine (Q); and         -   m) glutamine (Q) at position 326 is substituted with             glutamic acid (E).     -   E58. The polypeptide of embodiment E55, wherein said polypeptide         comprises a substitution for isoleucine (I) at position 141, a         substitution for threonine (T) at position 152, a substitution         for arginine (R) at position 192, a substitution for aspartic         acid (D) at position 197, a substitution for serine (S) at         position 241, and a substitution for glutamine (Q) at position         326.     -   E59. The polypeptide of embodiment E55, wherein said polypeptide         comprises a substitution of threonine (T) or alanine (A) for         isoleucine (I) at position 141, a substitution alanine (A) or         arginine (R) for threonine (T) at position 152, a substitution         of alanine (A) for arginine (R) at position 192, a substitution         of lysine (K) for aspartic acid (D) at position 197, a         substitution of threonine (T) for serine (S) at position 241,         and a substitution of glutamic acid (E) for glutamine (Q) at         position 326.     -   E60. The polypeptide of embodiment E55, wherein said polypeptide         comprises a substitution of threonine (T) for isoleucine (I) at         position 141, a substitution alanine (A) for threonine (T) at         position 152, a substitution of alanine (A) for arginine (R) at         position 192, a substitution of lysine (K) for aspartic acid (D)         at position 197, a substitution of threonine (T) for serine (S)         at position 241, and a substitution of glutamic acid (E) for         glutamine (Q) at position 326.     -   E61. The polypeptide of embodiment E55, wherein said polypeptide         comprises a substitution of alanine (A) for isoleucine (I) at         position 141, a substitution alanine (A) for threonine (T) at         position 152, a substitution of alanine (A) for arginine (R) at         position 192, a substitution of lysine (K) for aspartic acid (D)         at position 197, a substitution of threonine (T) for serine (S)         at position 241, and a substitution of glutamic acid (E) for         glutamine (Q) at position 326.     -   E62. The polypeptide of embodiment E55, wherein said polypeptide         comprises a substitution for isoleucine (I) at position 141, a         substitution for threonine (T) at position 152, a substitution         for aspartic acid (D) at position 197, a substitution for         serine (S) at position 241, and a substitution for glutamine (Q)         at position 326.     -   E63. The polypeptide of embodiment E55, wherein said polypeptide         comprises a substitution for isoleucine (I) at position 141, a         substitution for threonine (T) at position 152, a substitution         for arginine (R) at position 192, a substitution for aspartic         acid (D) at position 197, and a substitution for serine (S) at         position 241.     -   E64. The isolated polypeptide of embodiment E55, wherein said         polypeptide comprises a substitution of alanine (A) or         threonine (T) for isoleucine (I) at position 141, a substitution         of arginine (R) or alanine (A) for threonine (T) at position         152, a substitution of lysine (K) for aspartic acid (D) at         position 197, a substitution of threonine (T) for serine (S) at         position 241, and a substitution of glutamic acid (E) for         glutamine (Q) at position 326.     -   E65. The isolated polypeptide of embodiment E55, wherein said         polypeptide comprises a substitution of alanine (A) for         isoleucine (I) at position 141, a substitution of arginine (R)         for threonine (T) at position 152, a substitution of lysine (K)         for aspartic acid (D) at position 197, a substitution of         threonine (T) for serine (S) at position 241, and a substitution         of glutamic acid (E) for glutamine (Q) at position 326.     -   E66. The polypeptide of embodiment E55, wherein said polypeptide         comprises a substitution of alanine (A) for isoleucine (I) at         position 141, a substitution of alanine (A) for threonine (T) at         position 152, a substitution of lysine (K) for aspartic acid (D)         at position 197, a substitution of threonine (T) for serine (S)         at position 241, and a substitution of glutamic acid (E) for         glutamine (Q) at position 326.     -   E67. The polypeptide of embodiment E55, wherein said polypeptide         comprises a substitution of threonine (T) for isoleucine (I) at         position 141, a substitution of alanine (A) for threonine (T) at         position 152, a substitution of lysine (K) for aspartic acid (D)         at position 197, a substitution of threonine (T) for serine (S)         at position 241, and a substitution of glutamic acid (E) for         glutamine (Q) at position 326.     -   E68. The polypeptide in any one of embodiments E55 to E67,         wherein the at least one Pseudomonas exotoxin A (PE-A)         biological activity comprises the ability to inhibit in vitro         transcription/translation compared to a corresponding wild-type         or non-substituted PE-A polypeptide, wherein said ability to         inhibit in vitro transcription/translation is in an amount         selected from the group consisting of:         -   (a) at least 5% inhibition;         -   (b) at least 10% inhibition;         -   (c) at least 15% inhibition,         -   (d) at least 20% inhibition;         -   (e) at least 25% inhibition;         -   (f) at least 30% inhibition;         -   (g) at least 40% inhibition,         -   (h) at least 50% inhibition;         -   (i) at least 60% inhibition;         -   (j) at least 70% inhibition;         -   (k) at least 80% inhibition;         -   (l) at least 90% inhibition;         -   (m) at least 100% inhibition;         -   (n) about 100% inhibition; and         -   (o) 100% inhibition.     -   E69. The polypeptide in any one of embodiments E55 to E68,         comprising a number of amino acid substitutions selected from         the group consisting of:         -   a) 1 amino acid substitution;         -   b) 2 amino acid substitutions;         -   c) 3 amino acid substitutions;         -   d) 4 amino acid substitutions;         -   e) 5 amino acid substitutions; and         -   f) 6 amino acid substitutions.     -   E70. The polypeptide in any one of embodiments E55 to E69,         wherein said polypeptide comprises one or more amino acid         substitutions which prevent or reduce host immunogenic responses         compared to the same polypeptide without said one or more amino         acid substitutions.     -   E71. The polypeptide of embodiment E70, wherein host immunogenic         responses are prevented or reduced in a human host.     -   E72. The polypeptide in any one of embodiments E55 to E71,         wherein the last five or six amino acids in said polypeptide         comprise one or more amino acid sequences selected from the         group consisting of:         -   (i) Arg-Glu-Asp-Leu-Lys;         -   (ii) Arg-Glu-Asp-Leu;         -   (iii) Lys-Asp-Glu-Leu;         -   (iv) Glu-Asp-Leu-Lys; and         -   (v) a dimer, trimer, pentamer, hexamer, septamer, or octamer             of (i), (ii), or (iii), or any combination thereof.     -   E73. The polypeptide of any one of embodiments E55 to E72,         wherein said polypeptide has one or more biological activities         selected from the group consisting of:         -   a) eukaryotic cell killing activity (cell cytotoxicity);         -   b) inhibits translation elongation factor EF-2 biological             activity;         -   c) induces or catalyzes ADP-ribosylation of EF-2; and         -   d) inhibits protein synthesis.     -   E74. The polypeptide of any one of embodiments E55 to E72,         wherein said one or more amino acid substitutions prevent or         reduce host immunogenic responses compared to the same         polypeptide without the corresponding said one or more amino         acid substitutions,     -   E75. A polypeptide comprising a biologically active fragment of         the polypeptide in any one of embodiments E55 to E74.     -   E76. A polypeptide comprising a variant or derivative of the         polypeptide in any one of embodiments E55 to E75, wherein said         variant or derivative shares amino acid sequence identity with         the polypeptide in any one of embodiments E55 to E75, wherein         said shared amino acid sequence identity is selected from the         group consisting of:         -   a) at least 80% identity;         -   b) at least 85% identity;         -   c) at least 90% identity;         -   d) at least 95% identity;         -   e) at least 97% identity;         -   f) at least 98% identity; and         -   g) at least 99% identity.     -   E77. The polypeptide of any one of embodiments E55 to E76,         wherein said one or more amino acid substitutions prevent or         reduce host immunogenic responses compared to a polypeptide         comprising an amino acid sequence selected from the group         consisting of:         -   (a) SEQ ID NO:1;         -   (b) SEQ ID NO:4;         -   (c) SEQ ID NO:133; and         -   (d) SEQ ID NO:134.     -   E78. The polypeptide of any one of embodiments E55 to E77,         wherein said polypeptide is a fusion protein.     -   E79. The fusion protein of embodiment E78, wherein the         amino-terminal end of said polypeptide in any one of embodiments         E55 to E78 is fused to the carboxyl-terminal end of a different         polypeptide.     -   E80. The fusion protein of embodiment E78, wherein the         carboxyl-terminal end of said polypeptide in any one of         embodiments E55 to E78 is fused to the amino-terminal end of a         different polypeptide.     -   E81. The fusion protein in embodiment E79 or E80, wherein said         different polypeptide comprises an antigen binding moiety.     -   E82. The fusion protein of embodiment E81, wherein said antigen         binding moiety is an antibody or fragment thereof.     -   E83. The fusion protein of any one of embodiments E78 to E82,         wherein said antibody, or fragment thereof, is an antibody         selected from the list in Table 1, or is a fragment thereof.     -   E84. The fusion protein of embodiment E82, wherein said         antibody, or fragment thereof, specifically binds to a         cancer-specific or tumor-specific antigen.     -   E85. The fusion protein of embodiment E84, wherein said         cancer-specific or tumor-specific antigen is a breast cancer         antigen.     -   E86. The fusion protein of embodiment E85, wherein said breast         cancer antigen is HER2.     -   E87. The fusion protein of embodiment E82, wherein said         antibody, or fragment thereof is selected from the group         consisting of:         -   a) ERTUMAXOMAB (Rexomun);         -   b) PERTUZUMAB (Omnitarg); and         -   c) TRASTUZUMAB (Herceptin).     -   E88. The fusion protein of any one of embodiments E78 to E80,         wherein said different polypeptide comprises a polypeptide         selected from the group consisting of:         -   a) Mesothelin;         -   b) CD24;         -   c) CD22;         -   d) CD25;         -   e) CD174;         -   f) TPBG;         -   g) CD56; and         -   h) C-type lectin-like molecule-1.     -   E89. A polynucleotide encoding the polypeptide or fusion protein         in any one of embodiments E55 to E88.     -   E90. An expression vector comprising the polynucleotide of         embodiment E89.     -   E91. A host cell comprising the expression vector of embodiment         E90.     -   E92. A method of producing the polypeptide or fusion protein in         any one of embodiments E55 to E88, wherein said method         comprises:         -   a) obtaining a host cell comprising a polynucleotide             encoding said polypeptide or fusion protein;         -   b) exposing said host cell to conditions wherein said             polypeptide or fusion protein is produced.     -   E93. A method of producing the polypeptide or fusion protein in         any one of embodiments E55 to E88, wherein said method comprises         use of an expression system comprising:         -   (A) a first polynucleotide encoding a first hybrid             polypeptide comprising:             -   (i) a first ligand binding domain; and             -   (ii) a DNA-binding domain;         -   (B) a second polynucleotide encoding a second hybrid             polypeptide comprising:             -   (i) a second ligand binding domain; and             -   (ii) a transactivation domain;         -   (C) a third polynucleotide encoding the polypeptide or             fusion protein in any one of embodiments E55 to E88, wherein             said third polynucleotide is operably associated with a             response element capable of being bound by the DNA-binding             domain of said first hybrid polypeptide;     -   wherein the first ligand binding domain and the second ligand         binding domain are capable of ligand-induced dimerization,     -   wherein expression of the polypeptide or fusion protein in any         one of embodiments E55 to E88 is modulated by a ligand which         induces dimerization of said first and said second ligand         binding domains,     -   wherein the polypeptide or fusion protein in any one of         embodiments E55 to E88 is produced by allowing said ligand to         contact said first and said second ligand binding domains.     -   E94. A single expression vector or two or more expression         vectors comprising the first, second, and third polynucleotides         of embodiment E93.     -   E95. The expression vector or expression vectors of embodiment         E94, wherein one or more of the vectors is a viral expression         vector.     -   E96. A host cell comprising the expression vector or expression         vectors of embodiments E94 or E95.     -   E97. A method of treating a disease or disorder comprising         administering to a subject in need thereof the polypeptide or         fusion protein in any one of embodiments E55 to E88, the         polynucleotide of embodiment E89, the expression vector or         expression vectors in any one of embodiments E90, E94 or E95,         the host cell of embodiments E91 or E96, or a polypeptide or         fusion protein produced by the method of embodiment E92.     -   E98. A method of treating a disease or disorder comprising         delivering to a subject in need thereof a polypeptide or fusion         protein produced by the method of embodiment E93, wherein said         method comprises administration of the ligand to said subject.     -   E99. The method of embodiment E44, wherein the polypeptide or         fusion protein is delivered to the subject by first         administering the first, second, and third polynucleotides.     -   E100. The method of embodiment E98, wherein the polypeptide or         fusion protein is delivered to the subject by first         administering the expression vector or expression vectors of         embodiments E94 or E95.     -   E101. The method of embodiment E98, wherein said polypeptide or         fusion protein is delivered to the subject by first         administering the host cell of embodiments E91 or E96.     -   E102. A pharmaceutical composition comprising the polypeptide or         fusion protein in any one of embodiments E55 to E88, comprising         the polynucleotide of embodiment E89, comprising the expression         vector or expression vectors in any one of embodiments E90, E94         or E95, or comprising the host cell of embodiments E91 or E96,         and a pharmaceutically acceptable carrier, diluent or excipient.     -   E103. A medicament comprising the polypeptide or fusion protein         in any one of embodiments E55 to E88, comprising the         polynucleotide of embodiment E89, comprising the expression         vector or expression vectors in any one of embodiments E90, E94         or E95, or comprising the host cell of embodiments E91 or E96.     -   E104. Use of the pharmaceutical composition of embodiment E102         or the medicament of embodiment E103, wherein said use is for         the treatment of a disease or disorder.     -   E105. Use of the pharmaceutical composition or the medicament         according to embodiment E104, wherein the disease or disorder is         cancer.     -   E106. An Pseudomonas exotoxin A (PE-A) polypeptide, wherein said         polypeptide comprises a mutation at a position corresponding to         amino acid position E184 in SEQ ID NO:1 (or position E196 in SEQ         ID NO:2) wherein an isoleucine at position E184 (or position 196         in SEQ ID NO:2) is substituted with a different amino acid.     -   E107. The polypeptide of embodiment E106, wherein said         polypeptide does not have PE-A biological activity.     -   E108. A method for assaying the immunogenicity of a mutated form         of Pseudomonas exotoxin A (PE-A), wherein said method comprises:         -   (a) contacting immune cells with a mutated form of PE-A; and         -   (b) assaying immune cell stimulation,     -   wherein said mutated form of PE-A comprises a mutation at a         position corresponding to amino acid position E184 in SEQ ID         NO:1 (or position 196 in SEQ ID NO:2) wherein an isoleucine at         position E184 (or position 196 in SEQ ID NO:2) is substituted         with a different amino acid, and wherein said mutated form of         PE-A also comprises one or more additional amino acid         substitutions compared to a wild-type form of PE-A.     -   E109. The method of embodiment E108, wherein said immune cells         are human immune cells.     -   E110. The method of embodiment E109, wherein said immune cells         are human T-cells, cells of a human T-cell lineage, human         B-cells, or cells of a human B-cell lineage.     -   E111. The method of embodiment E47, wherein the ligand is a         compound having Formula I, or a pharmaceutically acceptable salt         thereof.     -   E112. The method of embodiment E47, wherein the ligand is a         compound having Formula II, or a pharmaceutically acceptable         salt thereof.     -   E113. The method of embodiment E47, wherein the ligand is a         compound having Formula III, or a pharmaceutically acceptable         salt thereof.     -   E114. The method of embodiment E47, wherein the ligand is a         compound of Table 3, or a pharmaceutically acceptable salt         thereof.     -   E115. The method of embodiment E47, wherein the ligand is a         compound having Formula III, wherein:         -   A is:

-   -   -   B is:

-   -   -   R^(3a), R^(3b), R^(3c), R^(3d), R^(3e), R^(3f), R^(3g),             R^(3h), R^(3i) and R^(3j) are independently selected from             hydrogen, halo, (C₁-C₄)alkyl, or (C₁-C₄)alkoxy;         -   R¹ is (C₁-C₆)alkyl, hydroxy(C₁-C₄)alkyl, or (C₂-C₄)alkenyl;             and         -   R² is optionally substituted (C₁-C₆)alkyl, or a             pharmaceutically acceptable salt thereof.

    -   E116. The method of embodiment E47, wherein the ligand is a         compound selected from the group consisting of:

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(2-ethyl-3-methoxy-benzoyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N′-benzoyl-N-(1-tert-butyl-butyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(2-methyl-benzoyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(2-methoxy-benzoyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(2-fluoro-benzoyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(2-chloro-benzoyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N′-(2-bromo-benzoyl)-N-(1-tert-butyl-butyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(3-methyl-benzoyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(3-methoxy-benzoyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(3-chloro-benzoyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(4-methyl-benzoyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(4-ethyl-benzoyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(4-methoxy-benzoyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(4-chloro-benzoyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(2,6-difluoro-benzoyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(2,6-dichloro-benzoyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(3,4-dimethoxy-benzoyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(3,5-difluoro-benzoyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(3,5-dimethoxy-4-methyl-benzoyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(4-methyl-benzo[1,3]dioxole-5-carbonyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(5-methyl-2,3-dihydro-benzo[1,4]dioxine-6-carbonyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(5-ethyl-2,3-dihydro-benzo[1,4]dioxine-6-carbonyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(naphthalene-1-carbonyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(naphthalene-2-carbonyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(thiophene-2-carbonyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(2,5-dimethyl-furan-3-carbonyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(2-chloro-pyridine-3-carbonyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(6-chloro-pyridine-3-carbonyl)-hydrazide;

-   (R)-3,5-Dimethyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(3-methoxy-2-methyl-benzoyl)-hydrazide;

-   (R)-3,5-Dimethoxy-4-methyl-benzoic acid     N-(1-tert-butyl-butyl)-N′-(3-methoxy-2-methyl-benzoyl)-hydrazide;     and

-   (R)-3,5-Dimethyl-benzoic acid     N′-(4-ethyl-benzoyl)-N-(1-phenethyl-but-3-enyl)-hydrazide,     -   or a pharmaceutically acceptable salt thereof.

EXAMPLES Example 1: T Cell Epitope Mapping of PE

Peptides spanning the sequence of an approximately 38 kD form of Pseudomonas exotoxin A protein (“PE38”) were analyzed for the presence of immunogenic CD4+ T cell epitopes using EPISCREEN™ T cell epitope mapping analysis (Antitope Ltd, Cambridge, UK).

EPISCREEN™ is a proprietary technology commercially available through Antitope Ltd, Cambridge, UK, to map T cell epitopes within a protein sequence to determine potential for immunogenicity (based on the number and potency of T cell epitopes within a sequence). EPISCREEN™ T cell epitope mapping typically uses CD8+ T cell depleted PBMCs from a minimum of 50 HLA-typed donors (selected to represent the human population of interest). Typically, 15 mer peptides with 12 amino acid overlaps spanning a protein sequence are analyzed in a large number of replicate cultures for in vitro CD4+ T cell stimulation by 3H TdR incorporation. CD4+ T cell stimulation is often detected in two or three adjacent and overlapping peptides since the core 9 mer that binds the MHC class II binding groove will be present in more than one peptide sequence. Following identification of peptides that stimulate CD4+ T cells in vitro, in silico technology can be used to design epitope-depleted (deimmunized) variants by determining the precise location of core 9 mer sequences and the location of key MHC class II anchor residues.

A total of 120 overlapping 15 mer peptides spanning the entire PE38 sequence (SEQ ID NO:2), including 4 peptides covering a null mutation and 4 peptides spanning an N-terminal linker sequence (SEQ ID NO:3) were tested against a cohort of 52 healthy donors. CD4+ T cell responses against individual peptides were measured using proliferation assays (3H-thymidine incorporation). The proliferation assay data was used to compile a T cell epitope map of the PE38 sequence and six T cell epitopes were identified.

EPISCREEN™ Donor Selection

Peripheral blood mononuclear cells (PBMC) were isolated from healthy community donor buffy coats (from blood drawn within 24 hours) obtained from the UK National Blood Transfusion Service (Addenbrooke's Hospital, Cambridge, UK) and according to approval granted by Addenbrooke's Hospital Local Research Ethics Committee. PBMC were isolated from buffy coats by LYMPHOPREP™ (Axis-Shield UK, Dundee, Scotland) density centrifugation. (LYMPHOPREP™ is a ready-made, sterile and endotoxin tested solution for the isolation of human mononuclear cells from blood. See, Axis-Shield, package insert for LYMPHOPREP™ density gradient media No. 619. March 2003. Div.-1114740.) CD8+ T cells were depleted using CD8+ ROSETTESEP™ (STEMCELL™ Technologies inc, Manchester, UK) to remove CD8+ cells from the isolated mononuclear cells. See e.g., StemCell Technologies Inc., ROSETTESEP™ procedure for Human CD8+ T Cell Enrichment Cocktail (Catalog #15023/15063, Procedure version 1.3.0, “#28572 (May 2011)).

HLA allotypes of donors were characterized using the Biotest HLA SSP-PCR tissue-typing kit (Biotest, Solihull, UK, catalogue number 826215). T cell responses to a reproducibility control neo-antigen were also determined using Imject maricutlure keyhole limpet haemocyanin (KLH) (Pierce (Perbio Science UK, Ltd)), Cramlington, UK, catalogue number 77600) with the KLH diluted to a final concentration of 100 μg/ml. PBMC were then frozen and stored in liquid nitrogen until required.

A cohort of 52 donors was selected to best represent the number and frequency of HLA-DR allotypes expressed in the world population. Analysis of the allotypes expressed in the cohort against those expressed in the world population revealed that coverage of >80% was achieved and that all major HLA-DR alleles (individual allotypes with a frequency >5% expressed in the world population) were well represented. Details of individual donor haplotypes and a comparison of the frequency of MHC class II haplotypes expressed in the world population and the sample population are shown in Table 7 and FIG. 2, respectively.

Table 7.

Donor details and haplotypes. Donor responses (SI) to KLH are shown for two independent proliferation assays. Test 1 was performed using KLH on freshly isolated PBMC and IEX01 is the KLH re-test performed in the current study on PBMC recovered from liquid nitrogen storage as indicated above. Responses that did not produce the same result (i.e. positive including borderline SI >1.90 p<0.05 or negative) in both tests are donors 3, 7, 9, 33 and 44.

TABLE 7 Donor Haplotypes and Responses KLH Donor Haplotype Test 1 IEX01  1 DRB1*15, DRB1*16; DRB5* 18.10 1.97  2 DRB1*03, DRB1*07; DRB3*; DRB4* 2.49 5.74  3 DRB1*11, DRB1*13; DRB3*; DRB4* 0.81 4.00  4 DRB1*03; DRB3* 1.73 1.78  5 DRB1*01, DRB1*13; DRB3*; DRB4* 0.99 1.05  6 DRB1*03, DRB1*14; DRB3* 2.91 2.01  7 DRB1*13, DRB1*14; DRB3*; DRB4* 3.13 1.20  8 DRB1*01, DRB1*07; DRB4* 2.49 5.74  9 DRB1*03, DRB1*07; DRB3*; DRB4* 0.81 4.00 10 DRB1*03, DRB1*15; DRB5 6.16 6.16 11 DRB1*01, DRB1*13; DRB3* 7.15 17.34 12 DRB1*13; DRB4*; DRB5* 7.98 2.76 13 DRB1*13, DRB1*14; DRB4* 1.00 1.81 14 DRB1*03, DRB1*13; DRB3* 2.28 2.70 15 DRB1*04, DRB1*11; DRB3*; DRB4* 8.96 1.91 16 DRB1*04, DRB1*14; DRB3*; DRB4* 5.85 4.01 17 DRB1*13, DRB1*15; DRB3*; DRB5* 19.16 2.69 18 DRB1*11, DRB1*13; DRB3* 10.32 6.48 19 DRB1*04, DRB1*15; DRB4* 2.70 3.39 20 DRB1*04, DRB1*07; DRB4* 0.51 1.27 21 DRB1*01, DRB1*04; DRB4* 1.71 1.05 22 DRB1*03; DRB3* 1.05 1.59 23 DRB1*04, DRB1*15; DRB4*; DRB5* 2.83 2.34 24 DRB1*01 1.63 1.09 25 DRB1*04, DRB1*15; DRB4*; DRB5* 1.12 1.44 26 DRB1*03, DRB1*07; DRB3*; DRB4* 1.18 0.84 27 DRB1*11, DRB1*13; DRB3* 8.80 14.30 28 DRB1*01, DRB1*07; DRB4* 3.68 4.53 29 DRB1*12, DRB1*13; DRB3* 3.68 2.40 30 DRB1*11; DRB3* 7.68 2.71 31 DRB1*03, DRB1*11; DRB3* 3.04 4.16 32 DRB1*13; DRB3* 1.96 2.22 33 DRB1*15; DRB4* 1.31 3.13 34 DRB1*03, DRB1*04; DRB3*; DRB4* 0.97 1.35 35 DRB1*12; DRB3*; DRB4* 3.51 2.55 36 DRB1*07; DRB3*; DRB4* 6.63 8.90 37 DRB1*04, DRB1*04; DRB4* 44.94 6.28 38 DRB1*01, DRB1*15; DRB3*; DRB4* 1.36 1.30 39 DRB1*07, DRB1*13; DRB3*; DRB4* 12.62 2.29 40 DRB1*03, DRB1*04; DRB3*; DRB4* 1.39 1.37 41 DRB1*07, DRB1*08; DRB4* 3.40 3.47 42 DRB1*07, DRB1*13; DRB3*; DRB4* 40.32 7.36 43 DRB1*13, DRB1*15; DRB3*; DRB5* 3.56 3.21 44 DRB1*11, DRB1*14; DRB3* 1.15 2.86 45 DRB1*03, DRB1*13; DRB3* 8.78 8.72 46 DRB1*03, DRB1*13; DRB3* 11.47 3.11 47 DRB1*03, DRB1*04; DRB3*; DRB4* 6.27 2.03 48 DRB1*04, DRB1*15; DRB5* 10.29 3.77 49 DRB1*07, DRB1*15; DRB4*; DRB5* 2.59 2.32 50 DRB1*04, DRB1*15; DRB4*; DRB5* 2.49 2.42 51 DRB1*11; DRB3*; DRB4* 8.30 2.09 52 DRB1*03, DRB1*13; DRB3* 3.99 6.22

EPISCREEN™ Analysis: Proliferation Assay

PBMC from each donor were thawed, counted and viability was assessed. Cells were revived in room temperature AIM V® culture medium (Invitrogen, Paisley, UK) before adjusting the cell density to 2-3×10⁶ PBMC/ml (proliferation cell stock). Peptides were synthesized on a 1-3 mg scale with free N-terminal amine and C-terminal carboxylic acid. Peptides were dissolved in DMSO to a concentration of 10 mM and peptide culture stocks prepared by diluting into AIM V® culture medium to a final concentration of 5 μM in the well. For each peptide and each donor, sextuplicate cultures were established in a flat bottomed 96 well plate. Both positive and negative control cultures were also tested in sextuplicate. For each donor, three control antigen/peptides (KLH protein and peptides derived from Influenza A and Epstein Barr viruses) were also included.

Cultures were incubated for a total of 6 days before adding 0.75 μCi 3[H]-thymidine (PERKIN ELMER®, Beaconsfield, UK) to each well. Cultures were incubated for a further 18 hours before harvesting onto filter mats using a TOMTEC MACH® III cell harvester (TOMTEC®, Hamden, Conn., USA). Counts per minute (cpm) for each well were determined by Meltilex™ (PERKIN ELMER®) scintillation counting on a Microplate Beta Counter (PERKIN ELMER®) in paralux, low background counting mode.

EPISCREEN™ Data Analysis

For proliferation assays, an empirical threshold of a stimulation index (SI) equal to or greater than 2 (SI≧2.00) has been previously established whereby samples inducing proliferative responses above this threshold are deemed positive (where included, borderline SI≧1.90 are highlighted). Extensive assay development and previous studies have shown that this is the minimum signal to noise threshold allowing maximum sensitivity without detecting large numbers of false positive responses. Positive responses are defined by the following statistical and empirical thresholds:

-   -   1. Significance (p<0.05) of the response by comparing cpm of         test wells against medium control wells using unpaired two         sample Student's t-test.     -   2. Stimulation index greater than 2.00 (SI≧2.00), where SI=mean         cpm of test wells/mean cpm medium control wells. Data presented         in this way is indicated as SI≧2.00, p<0.05.

In addition, intra-assay variation was assessed by calculating the coefficient of variance and standard deviation (SD) of the raw data from replicate cultures.

Proliferation assays were set up in sextuplicate cultures (“non-adjusted data”). To ensure that intra-assay variability was low, the data was also analyzed after removing the maximum and minimum cpm values (“adjusted data”) and the SI of donor responses was compared using both data sets.

T cell epitopes were identified by calculating the average frequency of positive responses (defined above) to all peptides in the study plus standard deviation (SD) to give a background response threshold. Any peptide that induced a frequency of positive proliferation responses above this threshold in both the adjusted and non-adjusted data was considered to contain an immunogenic T cell epitope (and, thus, potentially represents an immunogenicity inducing epitope which could give rise to immunogenic responses in vivo).

In Silico Analysis of Peptides

The sequences of peptides that were positive in the proliferation assay were analyzed using Antitope's predictive iTOPE™ software (Perry et al. 2008). This software predicts favorable interactions between amino acid side chains of the peptide and specific binding pockets within the MHC class II binding groove. Analysis of the peptide sequences using iTOPE™ was performed with overlapping 9 mers spanning the peptides which were tested against each of the 34 MHC class II alleles. Each 9 mer was scored based on the potential ‘fit’ and interactions with the MHC class II molecules. 9 mers that produced a high mean binding score were identified and, from the T cell proliferation data, 9 mers which were considered as critical to T cell responses (“core 9 mers”) were highlighted. iTOPE™ analysis was then repeated with a range of amino acid changes in the core 9 mers in order to determine preferred amino acid substitutions for use in deimmunization.

Results and Discussion

A total of 120 peptides were synthesized spanning the entire PE38 sequence. The peptides were designed as 15 mers to span the sequence in overlapping increments of 12 amino acids. These peptides were then tested for the presence of CD4+ T cell epitopes by EPISCREEN™ T cell epitope mapping analysis. Positive T cell responses were defined by donors that produced a significant (p<0.05) response with a SI≧2.00 to any given peptide (SI≧2.00, p<0.05). T cell epitopes were identified by calculating the average frequency of the positive responses to all peptides in the study plus SD (termed ‘background response threshold’). This was calculated to be 10.8% in the raw ‘non-adjusted’ data and 10.7% in the adjusted data (where maximum and minimum values were removed and the mean cpm calculated on the remaining four wells). Thus, peptides containing a T cell epitope induced positive T cell proliferation responses (SI≧2.00, p<0.05) in ≧6 donors in the non-adjusted and adjusted data sets. Inter-assay variability was assessed using KLH as a reproducibility control where the frequency of positive T cell responses against KLH were compared in two separate EPISCREEN™ assays (Table 7). The results show that inter-assay variability is within the acceptable range and consistent with previous studies (≦10%), The frequency of T cell responses against the two control peptides C3 (EBNA derived epitope) and C32 (Influenza derived epitope) ranged between 23-31% (non-adjusted) and between 21-29% (adjusted) for the two peptides, respectively (FIG. 3). This is within the typical range observed for these two peptides in T cell epitope mapping studies.

The output from non-adjusted and adjusted data analysis was examined to ensure that intra-assay variability was low and that positive responses were not the result of spurious proliferation in individual wells. The results from each analysis showed, in most cases, only small differences between the methods and donor responses for both non-adjusted and adjusted analysis. Table 10 provides a summary of individual donor responses to each of the peptides. The proliferation assay data showing the frequency of positive donor responses to each peptide is shown in FIG. 3. For all peptides that induced a high frequency of positive (SI≧2.00, p<0.05, including borderline responses) T cell proliferation responses above the background response threshold, additional in silico analysis was performed to aid in the identification of the precise location of MHC class II core 9 mer binding registers (using iTOPE™), and to identify peptides that are homologous to sequences containing T cell epitopes that have been tested in previous EPISCREEN™ T cell epitope mapping assays (using TCED™).

Table 8.

Summary of individual donor responses to PE38 peptides. Positive responses (SI≧2.00, p<0.05, including borderline responses) are indicated by the donor number and individual SI are shown in parentheses next to the corresponding donor. The background response rate was 10.8% in the non-adjusted data and 10.7% in the adjusted data peptides inducing positive T cell proliferation above this frequency (positive response in ≧6 donors) contained T cell epitopes (i.e., peptides 50, 52, 53, 65, 67, 68, 81, 82 and 110 (also as indicated in FIGS. 3-6)).

TABLE 8 Donor Responses to PE38 Peptides Peptide # Proliferation Non-Adjusted Proliferation Adjusted Peptide Sequence 1 11(2.25), 19(2.42), 25(3.24), 11(2.34), 19(2.72), GGGGGSGGGGGSPEG 35(2.77), 36(2.21) 25(3.33), 35(2.76), (SEQ ID NO: 11) 36(2.10) 2 19(2.44), 36(1.94) 19(2.67), 48(2.06) GGSGGGGGSPEGGSL (SEQ ID NO: 12) 3 11(1.98), 16(1.92), 19(2.54) 11(1.99), 19(2.78), GGGGGSPEGGSLAAL 38(5.37) (SEQ ID NO: 13) 4 16(2.33), 17(2.02), 19(2.29), 16(2.13), 17(2.02), GGSPEGGSLAALTAH 35(2.33) 19(2.46), 35(2.35), (SEQ ID NO: 14) 38(3.71) 5 7(1.97), 10(2.24), 17(2.24), 7(2.05), 10(2.46), PEGGSLAALTAHQAC 24(1.90) 17(2.20) (SEQ ID NO: 15) 6 3(2.00) GSLAALTAHQACHLP (SEQ ID NO: 16 7 3(2.11), 17(2.39), 24(2.20), 3(2.30), 17(2.22), AALTAHQACHLPLET 45(2.11) 24(2.11), 45(1.90) (SEQ ID NO: 17) 8 17(2.23), 45(2.12) 17(2.04) TAHQACHLPLETFTR (SEQ ID NO: 18) 9 — — QACHLPLETFTRHRQ (SEQ ID NO: 19) 10 — — HLPLETFTRHRQPRG (SEQ ID NO: 20) 11 10(2.48), 24(2.13) 7(1.98), 10(2.90), LETFTRHRQPRGWEQ 24(2.12) (SEQ ID NO: 21) 12 — 7(1.95) FTRHRQPRGWEQLEQ (SEQ ID NO: 22) 13 10(3.20), 24(2.12) 10(7.11), 24(2.12) HRQPRGWEQLEQCGY (SEQ ID NO: 23) 14 10(2.14), 17(2.47), 24(2.06) 1(2.22), 10(2.04), PRGWEQLEQCGYPVQ 17(2.25), 24(2.17), (SEQ ID NO: 24) 51(1.91) 15 17(2.04), 24(2.24) 17(2.05), 24(2.21) WEQLEQCGYPVQRLV (SEQ ID NO: 25) 16 — — LEQCGYPVQRLVALY (SEQ ID NO: 26) 17 — — CGYPVQRLVALYLAA (SEQ ID NO: 27) 18 — — PVQRLVALYLAARLS (SEQ ID NO: 28) 19 — — RLVALYLAARLSWNQ (SEQ ID NO: 29) 20 3(2.35), 40(1.96) 3(9.55), 8(2.06), 9(1.90), ALYLAARLSWNQVDQ 19(1.94), 40(2.07) (SEQ ID NO: 30) 21 11(1.90) 3(4.22), 8(2.22), LAARLSWNQVDQVIR 11(2.17), 40(1.96) (SEQ ID NO: 31) 22 3(2.20), 40(2.10) 3(4.32), 6(2.17), RLSWNQVDQVIRNAL 19(2.00), 40(2.15) (SEQ ID NO: 32) 23 6(2.24), 19(1.97) 3(4.67), 6(2.40), WNQVDQVIRNALASP 19(2.22), (SEQ ID NO: 33) 24 3(3.08) 3(3.99) VDQVIRNALASPGSG (SEQ ID NO: 34) 25 3(1.90), 6(1.92) 6(2.36) VIRNALASPGSGGDL (SEQ ID NO: 35) 26 — — NALASPGSGGDLGEA (SEQ ID NO: 36) 27 — — ASPGSGGDLGEAIRE (SEQ ID NO: 37) 28 24(2.62) 9(1.99), 11(1.92), GSGGDLGEAIREQPE 24(3.47), (SEQ ID NO: 38) 29 4(2.05), 17(2.07), 45(2.18) 4(1.91), 17(1.96), GDLGEAIREQPEQAR 24(2.29), 45(2.18) (SEQ ID NO: 39) 30 17(1.94) 8(2.54), 17(2.18), GEAIREQPEQARLAL 24(2.44) (SEQ ID NO: 40) 31 — — IREQPEQARLALTLA (SEQ ID NO: 41) 32 — 31(1.96) QPEQARLALTLAAAE (SEQ ID NO: 42) 33 — — QARLALTLAAAESER (SEQ ID NO: 43) 34 — — LALTLAAAESERFVR (SEQ ID NO: 44) 35 4(1.91), 35(1.91), 29(2.42), 35(1.98), TLAAAESERFVRQGT 37(2.18), 42(2.05) 36(2.05), 37(2.27), (SEQ ID NO: 45) 42(2.07) 36 3(2.14), 42(1.91) 3(2.12), 29(3.71), AAESERFVRQGTGND 36(1.91) (SEQ ID NO: 46) 37 37(2.34), 42(1.96) 13(1.91), 29(3.91), SERFVRQGTGNDEAG 35(2.06), 37(2.20) (SEQ ID NO: 47) 38 37(2.20), 42(2.12) 29(2.28), 36(1.95), FVRQGTGNDEAGAAS 37(2.20), 42(2.06) (SEQ ID NO: 48) 39 42(1.90) — QGTGNDEAGAASGPA (SEQ ID NO: 49) 40 1(2.21) 1(2.08) GNDEAGAASGPADSG (SEQ ID NO: 50) 41 1(2.28) 1(2.16) EAGAASG PADSGDAL (SEQ ID NO: 51) 42 — — AASGPADSGDALLER (SEQ ID NO: 52) 43 — — GPADSGDALLERNYP (SEQ ID NO: 53) 44 17(2.08), 22(1.95), 42(2.02) 17(2.13), 22(2.00), DSGDALLERNYPTGA 37(1.98) (SEQ ID NO: 54) 45 — — DALLERNYPTGAEFL (SEQ ID NO: 55) 46 31(2.23) 31(1.98) LERNYPTGAEFLGDG (SEQ ID NO: 56) 47 — — NYPTGAEFLGDGGDI (SEQ ID NO: 57) 48 2(2.63) — TGAEFLGDGGDISFS (SEQ ID NO: 58) 49 — — EFLGDGGDISFSTRG (SEQ ID NO: 59) 50 10(2.54), 11(1.93), 19(2.29), 10(2.56), 11(2.33), GDGGDISFSTRGTQN 36(2.36), 37(1.92), 39(2.17), 19(2.37), 36(2.37), (SEQ ID NO: 60) 42(2.66), 45(1.96) 39(2.13), 42(2.63), 45(1.95), 46(1.93) 51 19(2.03), 42(2.25), 45(1.93) 2(2.57), 11(2.06), GDISFSTRGTQNWTV 19(1.97), 42(2.20), (SEQ ID NO: 61) 45(1.90) 52 3(7.10), 11(2.76), 16(2.41), 2(1.95), 3(6.19), SFSTRGTQNWTVERL 19(2.36), 42(1.97), 44(1.92) 11(3.01), 16(2.58), (SEQ ID NO: 62) 19(2.45), 42(2.02), 44(2.05) 53 2(2.13), 3(5.19), 11(1.98), 2(2.27), 3(4.50), TRGTQNWTVERLLQA 16(2.12), 19(2.19), 27(2.09), 11(2.01), 16(1.94), (SEQ ID NO: 63) 45(1.92) 19(2.10), 27(2.46) 54 — 3(1.90), 11(1.95), TQNWTVERLLQAHRQ 16(1.92) (SEQ ID NO: 64) 55 3(1.98) — WTVERLLQAHRQLEE (SEQ ID NO: 65) 56 — — ERLLQAHRQLEERGY (SEQ ID NO: 66) 57 — — LQAHRQLEERGYVFV (SEQ ID NO: 67) 58 10(2.67), 11(2.90) 9(1.99), 10(2.55), HRQLEERGYVFVGYH 11(3.46), 4(1.90) (SEQ ID NO: 68) 59 9(2.27), 37(2.56), 42(2.70) 9(2.38), 11(2.15), LEERGYVFVGYHGTF 37(2.71), 42(3.01) (SEQ ID NO: 69) 60 — 16(2.09) RGYVFVGYHGTFLEA (SEQ ID NO: 70) 61 — 11(2.07) VFVGYHGTFLEAAQS (SEQ ID NO: 71) 62 — — GYHGTFLEAAQSIVF (SEQ ID NO: 72) 63 3(2.88) 11(1.97), 16(2.02) GTFLEAAQSIVFGGV (SEQ ID NO: 73) 64 — — LEAAQSIVFGGVRAR (SEQ ID NO: 74) 65 2(2.17), 4(1.94), 14(3.63), 2(2.30), 4(1.93), AQSIVFGGVRARSQD 17(2.19), 18(2.46), 36(2.06), 11(2.10), 14(3.65), (SEQ ID NO: 75) 39(1.97), 51(7.91) 18(2.31), 36(2.09), 39(2.04), 51(6.71) 66 18(1.95), 19(1.90), 36(1.94), 19(2.02), 36(1.98), IVFGGVRARSQDLDA 51(10.38) 47(1.91), 51(9.41) (SEQ ID NO: 76) 67 6(2.07), 14(2.62), 16(2.21), 14(2.68), 16(2.55), GGVRARSQDLDAIWR 17(2.11), 18(2.60), 42(1.95), 18(2.42), 19(2.06), (SEQ ID NO: 77) 47(1.93), 51(6.83) 38(1.95), 47(1.95), 51(5.22) 68 2(2.07), 14(2.24), 18(2.70), 2(2.12), 11(2.11), RARSQDLDAIWRGFY 38(1.94), 39(2.05), 42(2.10), 14(2.04), 16(2.00), (SEQ ID NO: 78) 51(3.69) 19(2.06), 38(2.15), 39(2.17), 51(3.62) 69 31(1.95), 42(1.99), 51(2.47) 31(1.93), 51(2.19) SQDLDAIWRGFYIAG (SEQ ID NO: 79) 70 24(2.22) LDAIWRGFYIAGDPA (SEQ ID NO: 80) 71 — IWRGFYIAGDPALAY (SEQ ID NO: 81) 72 — — GFYIAGDPALAYGYA (SEQ ID NO: 82) 73 6(1.91), 14(2.70), 17(2.13), 11(2.02), 14(2.77), IAGDPALAYGYAQDQ 39(1.98) 17(1.94), 39(2.01) (SEQ ID NO: 83) 74 6(1.99), 14(2.77), 38(1.99), 14(2.89), 16(2.01), DPALAYGYAQDQEPD 39(2.25), 42(1.90) 39(2.27) (SEQ ID NO: 84) 75 6(2.22), 14(2.27), 17(1.93), 14(2.24), 16(2.26), LAYGYAQDQEPDARG 39(2.05) 39(2.07) (SEQ ID NO: 85) 76 14(2.20), 17(1.98) 14(2.40), 39(1.94) GYAQDQEPDARGRIR (SEQ ID NO: 86) 77 — 38(1.90) QDQEPDARGRIRNGA (SEQ ID NO: 87) 78 — — EPDARGRIRNGALLR (SEQ ID NO: 88) 79 — 24(1.91) ARGRIRNGALLRVYV (SEQ ID NO: 89) 80 9(2.89), 11(2.85), 19(2.18), 9(2.84), 19(2.03), RIRNGALLRVYVPRS 36(2.63), 42(2.23), 45(2.23) 36(2.59), 42(2.29), (SEQ ID NO: 90) 45(2.20) 81 1(2.08), 8(1.96), 9(2.05), 1(2.13), 9(2.05), NGALLRVYVPRSSLP 11(3.22), 13(2.09), 19(2.09), 13(2.10), 19(2.10), (SEQ ID NO: 91) 36(2.21), 42(2.31), 45(2.13), 36(2.15), 42(2.31), 49(2.07) 45(1.94), 49(2.00), 51(2.25) 82 9(1.93), 10(2.01), 11(2.41), 9(1.90), 10(2.00), LLRVYVPRSSLPGFY 13(2.09), 16( 2.11), 19(2.01), 13(2.21), 16(2.23), (SEQ ID NO: 92) 36(2.25), 45(1.97), 49(2.44) 19(1.98), 36(2.28), 45(1.98), 49(2.37) 83 33(2.02), 42(2.14), 46(1.90), 33(1.97), 42(2.14), VYVPRSSLPGFYRTG 49(1.92) 49(1.95) (SEQ ID NO: 93) 84 11(1.93) — PRSSLPGFYRTGLTL (SEQ ID NO: 94) 85 — — SLPGFYRTGLTLAAP (SEQ ID NO: 95) 86 — — GFYRTGLTLAAPEAA (SEQ ID NO: 96) 87 — — RTGLTLAAPEAAGEV (SEQ ID NO: 97) 88 9(2.59), 11(3.03), 42(2.03), 9(2.47), 42(2.01) LTLAAPEAAGEVERL 51(2.30) (SEQ ID NO: 98) 89 9(1.91), 11(4.31), 42(2.34), 11(2.05), 13(2.28), AAPEAAGEVERLIGH 49(2.09), 51(5.22) 42(2.16), 51(6.48) (SEQ ID NO: 99) 90 11(2.59), 14(2.07), 49(2.12), 14(2.11), 49(2.11), EAAGEVERLIGHPLP 51(7.78) 51(6.45) (SEQ ID NO: 100) 91 11(4.15), 42(1.99), 51(4.84) 42(2.06), 51(4.07) GEVERLIGHPLPLRL (SEQ ID NO: 101) 92 11(2.19), 49(1.99) — ERLIGHPLPLRLDAI (SEQ ID NO: 102) 93 — — IGHPLPLRLDAITGP (SEQ ID NO: 103) 94 — — PLPLRLDAITGPEEE (SEQ ID NO: 104) 95 3(2.10), 7(1.91), 18(1.90), 3(2.00), 7(1.95), LRLDAITGPEEEGGR 19(2.07), 35(2.17) 19(2.04), 45(2.03) (SEQ ID NO: 105) 96 3(2.62), 13(2.19), 16(2.18), 3(2.34), 13(2.46), DAITGPEEEGGRLET 39(1.96) 16(2.24), 31(1.93), (SEQ ID NO: 106) 39(2.10) 97 13(2.29), 16(2.32), 19(2.20), 13(2.48), 16(2.44), TGPEEEGGRLETILG 35(2.43), 45(2.13) 19(2.31), 45(2.16) (SEQ ID NO: 107) 98 11(1.92), 13(1.97), 16(2.26), 11(2.26), 13(2.04), EEEGGRLETILGWPL 35(1.91), 50(1.98) 16(2.33) (SEQ ID NO: 108) 99 35(2.33) — GGRLETILGWPLAER (SEQ ID NO: 109) 100 35(2.20) — LETILGWPLAERTVV (SEQ ID NO: 110) 101 — — ILGWPLAERTVVIPS (SEQ ID NO: 111) 102 27(1.93) — WPLAERTVVIPSAIP (SEQ ID NO: 112) 103 AERTVVIPSAIPTDP (SEQ ID NO: 113) 104 3(2.40), 16(2.20), 22(1.98), 3(2.17), 13(2.05), TVVIPSAIPTDPRNV 49(1.91) 16(2.15) (SEQ ID NO: 114) 105 16(2.43), 22(1.96), 45(1.97) 16(2.30), 45(1.95), IPSAIPTDPRNVGGD 49(1.96) (SEQ ID NO: 115) 106 16(2.02), 19(2.02) 16(1.95), 19(1.90) AIPTDPRNVGGDLDP (SEQ ID NO: 116) 107 19(2.00), 27(2.06) 19(1.93), 27(1.99) TDPRNVGGDLDPSSI (SEQ ID NO: 117) 108 — — RNVGGDLDPSSIPDK (SEQ ID NO: 118) 109 — — GGDLDPSSIPDKEQA (SEQ ID NO: 119) 110 8(2.07), 9(2.35), 11(2.27), 9(2.46), 10(2.04), LDPSSIPDKEQAISA 13(2.13), 16(1.91), 19(3.00), 13(2.11), 19(1.99), (SEQ ID NO: 120) 35(1.90) 35(1.94), 38(1.95), 50(2.01) 111 3(2.29), 8(2.20), 9(1.93), 3(2.33), 8(2.74), 9(2.02), SSIPDKEQAISALPD 11(2.08), 16(2.19), 19(2.60) 13(1.98) (SEQ ID NO: 121) 112 11(2.47), 16(3.07), 19(2.61) 9(1.90), 16(2.11), PDKEQAISALPDYAS 50(1.97) (SEQ ID NO: 122) 113 3(2.07), 11(2.61), 16(2.44), 3(2.04), 11(1.93), EQAISALPDYASQPG 19(2.62) 45(1.90) (SEQ ID NO: 123) 114 19(2.04) — ISALPDYASQPGKPP (SEQ ID NO: 124) 115 16(1.99) — LPDYASQPGKPPRED (SEQ ID NO: 125) 116 — — YASQPGKPPREDLK (SEQ ID NO: 126) 117 — — ITGPEEEGGRLDTIL (SEQ ID NO: 127) 118 9(2.04), 11(2.26), 16(2.12), 9(2.27) PEEEGGRLDTILGWP 39(1.93), 5 (SEQ ID NO: 128) 119 16(2.11), 39(2.13) 14(1.90), 38(1.96), EGGRLDTILGWPLAE 39(2.10) (SEQ ID NO: 129) 120 11(2.13), 39(2.05) 39(2.07) RLDTILGWPLAERTV (SEQ ID NO: 130)

T Cell Epitope Map

Epitopes 1 and 2—

Peptides 50, 52 and 53 induced a high number of positive T cell proliferation responses in the study cohort (Table 8 and FIG. 3). Peptide 50 showed the highest number of positive responses with 15.38% donors responding in the non-adjusted dataset, and 15.38% in the adjusted data set, (SI≧2.00, p<0.05). From in silico analysis, the proposed core 9 mer in this region is ISFSTRGTQ (SEQ ID NO:5). Peptides 52 and 53 induced lower frequencies of response with 11.54% and 13.46% positive donor responses in the non-adjusted dataset, and 13.46% and 11.54% in the adjusted datasets, respectively. A core 9 mer was identified in peptide 50 but was only partially present in peptides 52 and 53 suggesting that these peptides must contain a different T cell epitope. In silico analysis of peptides 52 and 53 did not identify any core HLA-DR restricted 9 mers so it is likely that the positive T cell responses seen are due to a HLA-DQ restricted T cell epitope.

The magnitude of T cell proliferation responses can provide an indication as to the T cell precursor frequency. In general, peptides that induce high frequency (of positive responses in the study cohort) and high magnitude T cell proliferation responses are a characteristic of ‘recall-like’ T cell responses in which the T cell pre-cursor frequency is high. In contrast, naive T cell responses are generally characterized by low magnitude T cell proliferation responses (with low T cell precursor frequencies). Peptides 52 and 53 induced moderately high magnitude T cell proliferation responses where the mean SI for positive (SI≧2.00, p<0.05) T cell responses in the non-adjusted and adjusted data sets were 3.09-2.89 (peptide 52) and 2.51-2.55 (peptide 53) (Table 9). Thus these peptides may induce T cell responses in clones that are present in high frequencies in healthy individuals and may be indicative of a memory T cell response. Peptide 50 induced lower magnitude T cell proliferation responses where the mean SI were 2.23 and 2.28 in the non-adjusted and adjusted datasets respectively suggesting that this peptide may induce a naïve T cell response (Table 9).

Epitopes 3 and 4

A cluster of T cell responses were observed around peptides 65-68 and the subsequent analysis revealed the presence of two T cell epitopes in this region. Peptide 65 stimulated positive T cell proliferation responses in 15.38% of the study cohort for both non-adjusted and adjusted datasets (Table 8 and FIG. 3) (SI≧2.00, p<0.05). The positive responses were high magnitude (mean SI of positive responses ranged from 3.04-2.89 in the non-adjusted and adjusted data sets) suggesting that the T cell precursor frequency in healthy donors against this epitope is high (Table 9). In silico analysis revealed a potential core 9 mer comprising IVFGGVRAR (FIG. 5; SEQ ID NO:7). Peptides 67 and 68 induced frequencies of response with 15.38% and 13.46% positive donor responses in the non-adjusted dataset, and 13.46% and 15.38% in the adjusted datasets, respectively. In silica analysis of these peptides did not identify any core HLA-DR 9 mers so it is likely that the positive T cell responses seen are due to a HLA-DQ restricted T cell epitope.

Epitope 5

Peptides 81 and 82 stimulated a number of T cell responses in the study cohort (Table 8 and FIG. 3). Peptide 81 had the highest frequency of response of all the peptides tested with a frequency of positive responses of 19.23% in the non-adjusted and 17.31% in the adjusted data set. For peptide 82, the frequency of positive response was 17.31% and 15.38% in the non-adjusted and adjusted data sets respectively. The positive responses were relatively low in magnitude (mean SI of positive responses ranged from 2.12 to 2.22 in the non-adjusted and adjusted data sets) suggesting that the T cell precursor frequency in healthy donors against this epitope is relatively low (Table 9). Adjacent peptide 80 induced a sub-threshold response. In silico analysis of peptides 81 and 82 suggested a core 9 mer of LRVYVPRSS (FIG. 6; SEQ ID NO:9).

Epitope 6

Peptide 110 induced positive T cell responses in 13.46% of the study cohort in non-adjusted and 13.46% in adjusted datasets (Table 8 and FIG. 3). The magnitude of positive proliferation responses was low with a mean SI of 2.23 for the non-adjusted dataset and 2.07 for the adjusted dataset (Table 9). There was also a sub-threshold response to peptide 111. In silico analysis of the peptides sequence revealed a core 9 mer, IPDKEQAIS (FIG. 7, SEQ ID NO:10) which, in addition to peptide 110, was also present in peptide 111.

Table 9. Summary of magnitude (mean SI and standard deviation) and frequency (% donor response) of positive T cell proliferation responses against peptides containing T cell epitopes for PE38. The position of p1 in potential core 9 mers are shown as underlined/bolded text (as predicted by iTOPE™) in peptides 50, 65, 81, 82 and 110.

TABLE 9 Magnitude and Frequency of Donor Responses Mean Response Frequency Mean (SD) (SD) Non- Non-Adjusted Adjusted Peptide Peptide Sequence Adjusted Adjusted Data Data  50 GDGGD I SFSTRGTQN 15.38% 15.38% 2.23 ± 0.28 2.28 ± 0.26 (SEQ ID NO: 60)  52 SFSTRGTQNWTVERL 11.54% 13.46% 3.09 ± 1.99 2.89 ± 1.50 (SEQ ID NO: 62)  53 TRGTQNWTVERLLQA 13.46% 11.54% 2.51 ± 1.18 2.55 ± 0.98 (SEQ ID NO: 63)  65 AQS I VFGGVRARSQD 15.38% 15.38% 3.04 ± 2.04 2.89 ± 1.64 (SEQ ID NO: 75)  67 GGVRARSQDLDAIWR 15.38% 13.46% 2.79 ± 1.65 2.69 ± 1.15 (SEQ ID NO: 77)  68 RARSQDLDAIWRGFY 13.46% 15.38% 2.40 ± 0.62 2.28 ± 0.54 (SEQ ID NO: 78)  81 NGAL L RVYVPRSSLP 19.23% 17.31% 2.22 ± 0.36 2.12 ± 0.12 (SEQ ID NO: 91)  82 L L RVYVPRSSLPGFY 17.31% 15.38% 2.14 ± 0.19 2.12 ± 0.17 (SEQ ID NO: 92) 110 LDPSS I PDKEQAISA 13.46% 13.46% 2.23 ± 0.38 2.07 ± 0.18 (SEQ ID NO: 120)

HLA Analysis

Analysis of the responding donor haplotypes was performed whereby an association between MHC class II allotype and a response to a particular peptide was considered possible if the frequency of the allotype within the responding population was double the frequency observed in the study cohort. This analysis was only carried out for peptides that induced positive responses above the background response rate in the adjusted data in the study cohort and was also restricted to allotypes expressed at higher frequencies (>5%) in the study population.

Analysis of responding donor allotypes (Table 10 and FIG. 8) revealed that there was a possible association between T cell responses to peptides 81, and 82 and MHC class II allotype HLA DRB1*07 which was expressed at twice the percentage of positively responding donors compared to the study population. Peptide 53 also had a possible association with DRB1*11, and peptides 82 and 110 showed possible associations with DRB1*15. It should be noted that further studies (such as MHC class II binding analysis) would be required to show conclusively that responses to the T cell epitope are associated with these allotypes as the present analysis was performed on a small group of responding donors.

Table 10. Frequency (expressed as a percentage) of responding donor allotypes compared to the frequency of allotypes expressed in the IEX01 study cohort. An association between MHC class II allotype and a response to a particular epitope was considered if the frequency of the allotype within the responding population was double the frequency observed in the study population in the adjusted data set. Possible associations are indicated in heavily bordered boxes. The analysis has been restricted to allotypes expressed at higher frequencies (>5%) in the study population.

TABLE 10 Frequency of responding donor allotypes versus frequency of allotypes in the IEX01 study cohort.

Results

The results show that six T cell epitopes were present in the PE38 sequence. Table 6 Table 11 and FIG. 8 summarize the location of the putative core 9 mers in each sequence along with the frequency and magnitude of T cell responses against each epitope. The T cell epitopes identified in PE38 were prioritized according to their potency based on the frequency and magnitude (mean SI) of positive donor responses to each peptide. However since the responding donor magnitudes were similar (Table 4 Table 9) for most epitopes, the ranking was mainly based on frequency of positive donor responses (from highest to lowest):

Epitope 5>Epitope 4>Epitope 3>Epitope 1>Epitope 2>Epitope 6

Deimmunization Strategy

The six epitope core 9 mer sequences were analyzed by proprietary software (iTOPE™) in order to identify mutations that remove the T cell epitopes by eliminating or significantly reducing binding to MHC class II (Table 11). As part of the strategy as to which residues to mutate, location within the structure was considered, especially whether the residue is buried, on the surface, or near active sites.

Table 11. Projected mutations to remove MHC class II binding (based upon iTOPE™ and crystal structure data).

TABLE 11 Location of Core 9-mers and Projected Mutations Amino Epi- Acids in Anchor Projected tope Sequence Residues Mutations Notes: 1 I 1 A, N, T, P1 (Ile) is partially Q, H surface exposed, therefore S all alternatives should F be possible. S 4 P6 and P9 changes T perform equally well, R 6 Q but are less preferred G 7 than P1 changes. T Q 9 N, T 2 G 1 HLA-DQ epitopes have a T strong negative preference Q for positively charged N 4 K, R residues in key anchor W positions. All four T 6 K, R mutations are equally V 7 preferred. E R 9 3 I 1 A, N P1 is buried, therefore A V is preferred. F P6 V is partially exposed. G 4 All mutations should be G tolerated. Preference is V 6 D, M, N D > M > N. R 7 A R 9 4 A 1 HLA-DQ epitopes have a R strong negative preference S for positively charged Q 4 K, R residues in key anchor D positions. All four L 6 mutations are equally D 7 K, R preferred. A I 9 5 L 1 A P1 is buried and close in R D, S, A the structure to epitope 3 V P1, therefore changes are Y 4 limited. For this epitope, V changes at P2 affect P 6 binding (D > S > A). R 7 P9 is mostly surface S exposed. Preferred S 9 D, E, N, changes are D, E, N, then K, P, T K > P > T. 6 I 1 A, N, T, P1 I is partially surface Q, H exposed, therefore all P alternatives should be D possible. K 4 T P4, P6 and P9 changes are E less preferred than P1 Q 6 D changes. P6 D ≧ P7 D > A 7 D P4 T. I S 9

Conclusions

EPISCREEN™ T cell epitope mapping of 120 overlapping 15 mer peptides including 112 spanning the entire PE38 sequence suggested six novel T cell epitopes. In silico analysis was used to identify potential core 9 mers for MHC binding and, together with structural analysis, was used as a basis for design of changes for re-engineering and deimmunizing PE38 in particular, and PE molecules in general.

Example 2: T Cell Epitope Mapping of Deimmunized/Amino Acid Substituted Forms of PE

The immunogenicity of amino acid substituted forms of PE can be assessed using the same procedures as described in Example 1. Accordingly, EPISCREEN™ T cell epitope mapping analysis (Antitope Ltd, Cambridge, UK) analysis permits identification of amino acid substituted epitopes in PE polypeptides, wherein the introduced amino acid changes result in reduced or undetectable immunogenicity (i.e., for generating deimmunized forms of PE) as compared to epitopes in corresponding forms of non-amino acid substituted PE polypeptides.

EPISCREEN™ is a proprietary technology commercially available through Antitope Ltd, Cambridge, UK, to map T cell epitopes within a protein sequence to determine potential for immunogenicity (based on the number and potency of T cell epitopes within a sequence). EPISCREEN™ T cell epitope mapping typically uses CD8+ T cell depleted PBMCs from a minimum of 50 HLA-typed donors (selected to represent the human population of interest). Typically, 15 mer peptides with 12 amino acid overlaps spanning a protein sequence are analyzed in a large number of replicate cultures for in vitro CD4+ T cell stimulation by 3H TdR incorporation. CD4+ T cell stimulation is often detected in two or three adjacent and overlapping peptides since the core 9 mer that binds the MHC class II binding groove will be present in more than one peptide sequence. Following identification of peptides that stimulate CD4+ T cells in vitro, in silico technology can be used to design epitope-depleted (deimmunized) variants by determining the precise location of core 9 mer sequences and the location of key MHC class II anchor residues.

In this case, amino acid substituted PE peptides are analyzed for the presence of immunogenic CD4+ T cell epitopes using EPISCREEN™ T cell epitope mapping analysis. For example, amino acid substituted 15 mer peptides (compared to non-substituted 15 mer peptides corresponding to a non-amino acid substituted form of PE) are tested against a cohort of healthy donors. CD4+ T cell responses against individual peptides are measured using proliferation assays (3H-thymidine incorporation). Proliferation assay data is used to compile a T cell epitope map of varying responses to amino acid substituted forms of PE to determine those amino acid changes producing reduced or abrogated immunogenic responses.

EPISCREEN™ Donor Assessments

Peripheral blood mononuclear cells (PBMC) are isolated from healthy donor buffy coats (e.g., from blood drawn within 24 hours). For example, PBMC are isolated from buffy coats using density gradient centrifugation using LYMPHOPREP™ (Axis-Shield UK, Dundee, Scotland) or a similar density gradient centrifugation media for the isolation of human mononuclear cells from blood (such methods, media and products are well known and routinely used by those skilled in the art). See e.g., Axis-Shield, package insert for LYMPHOPREP™ density gradient media No. 619. March 2003. Div.-1114740.) To remove CD8+ cells from the isolated mononuclear cells, CD8+ T cells are depleted using CD8+ ROSETTESEP™ kit (STEMCELL™ Technologies Inc, Manchester, UK) or similar CD8+ selection methods and techniques (such methods, media and products are well known and routinely used by those skilled in the art). See e.g., StemCell Technologies Inc., ROSETTESEP™ procedure for Human CD8+ T Cell Enrichment Cocktail (Catalog #15023/15063; Procedure version 1.3.0, “#28572 (May 2011)).

Donors HLA-DR haplotypes are determined using methods or kits well-known and routinely used by those skilled in the art. For example, Donors HLA-DR haplotypes are determined using a Biotest HLA SSP-PCR tissue-typing kit (Biotest, Solihull, UK, catalogue number 826215). T cell responses to a reproducibility control antigen are measured using, for example neo-antigen, using Imject mariculture keyhole limpet haemocyanin (KLH) (Pierce (Perbio Science UK, Ltd), Cramlington, UK, catalogue number 77600), or other similar control antigen (such antigens and methods are well known and routinely used by those skilled in the art). PBMC are frozen and stored in liquid nitrogen until ready for use in to measuring immunogenicity of amino acid substituted forms of PE.

A cohort of donors are selected to best represent the number and frequency of HLA-DR allotypes expressed in the world population. It is desirable that allotypes expressed in the cohort represent a coverage of >80% of all major HLA-DR alleles in the world population (i.e., individual allotypes with a frequency >5% expressed in the world population are well represented). Records of individual donor haplotypes and comparison of the frequency of MHC class II haplotypes expressed in the world population and the sample population are recorded and assessed.

Donor responses (SI) to a control antigen (such as KLH) are assessed by comparing two independent proliferation assays. Test-1 is performed using the control antigen (such as KLH) on freshly isolated PBMC and Test-2 is the control antigen re-test performed on PBMC recovered from liquid nitrogen storage, the latter of which are used in assessing immunogenicity of amino acid substituted epitopes in PE. Responses that do not produce the same result in these two tests (i.e. positive including borderline SI>1.90 p<0.05 or negative) in both tests are disregarded.

EPISCREEN™ Analysis: Proliferation Assay

PBMC from each donor are thawed, counted and viability is assessed. Cells are revived in room temperature AIM V® Culture Medium (INVITROGEN™, Paisley, UK) before adjusting cell density to 2-3×10⁶ PBMC/ml (proliferation cell stock). Peptides are synthesized on a 1-3 mg scale with free N-terminal amine and C-terminal carboxylic acid. Peptides are dissolved in DMSO to a concentration of 10 mM and peptide culture stocks are prepared by diluting into AIM V® Culture Medium to a final concentration of 5 μM per well. For each peptide and each donor, sextuplicate cultures are established in a flat bottomed 96 well plate. Both positive and negative control cultures are tested in sextuplicate. For each donor, three control antigen/peptides (KLH protein and peptides derived from Influenza A and Epstein Barr viruses) are also included.

Cultures are incubated for 6 days before adding 0.75 μCi 3[H]-thymidine (PERKIN ELMER®, Beaconsfield, UK) to each well. Cultures are incubated a further 18 hours before harvesting onto filter mats using a TOMTEC MACH® III cell harvester (TOMTEC®, Hamden, Conn., USA). Counts per minute (cpm) for each well are determined by MELTILEX™ (PERKIN ELMER®) scintillation counting on a Microplate Beta Counter (PERKIN ELMER®) in paralux, low background counting mode.

EPISCREEN™ Data Analysis

In proliferation assays, an empirical threshold of stimulation index (SI) equal to or greater than 2 (SI≧2.00) is considered to represent an induced proliferative response; samples registering values above this threshold are deemed positive (values of SI<2.00 but ≧1.90 are considered borderline). Extensive assay development and previous studies have shown that this is the minimum signal to noise threshold allowing maximum sensitivity without detecting large numbers of false positive responses. Positive responses are defined by the following statistical and empirical thresholds:

-   -   1. Significance (p<0.05) of the response by comparing cpm of         test wells against medium control wells using unpaired two         sample Student's t-test.     -   2. Stimulation index greater than 2.00 (SI≧2.00), where SI=mean         cpm of test wells/mean cpm medium control wells. Thus, data         presented is indicated as SI≧2.00, p<0.05.

In addition, intra-assay variation is assessed by calculating the coefficient of variance and standard deviation (SD) of raw data from replicate cultures.

Proliferation assays are set up in sextuplicate cultures from which “non-adjusted data” is gathered. To ensure intra-assay variability is low, data is also analyzed after removing maximum and minimum cpm values (to produce “adjusted data”) and the SI of donor responses is compared using both data sets.

Reactive T cell epitopes are identified by calculating the average frequency of positive responses (defined above) to all peptides in the study plus standard deviation (SD) to give a background response threshold. Any peptide inducing a frequency of positive proliferation responses above the threshold in both adjusted and non-adjusted data is considered to contain an immunogenic T cell epitope (and, thus, potentially represents an immunogenicity inducing epitope which could give rise to immunogenic responses in vivo). Output from non-adjusted and adjusted data is examined to ensure that intra-assay variability is low and that positive responses are not the result of spurious proliferation in individual wells. An example of this type of analysis is provided in Example 1.

A comparison of corresponding forms of non-amino acid substituted PE immunogenic epitope responses versus responses obtained with amino acid substituted PE peptides is used to assess and predict the effects of various amino acid substitutions in reducing or eliminating the immunogenicity of PE polypeptides (i.e., for making deimmunized forms of PE).

Assays for measuring and testing the immunogenicity of amino acid substituted forms of PE may also be done as described and exemplified in Example 1 (i.e., via proliferation assays quantitating CD4+ T cell responses) wherein amino acid substituted forms of PE (i.e., “deimmunized PE” or “DI-PE”), and/or DI-PE conjugates and fusion proteins (e.g., fusions of DI-PE to antibodies or antigen-binding fragments thereof) are tested and measured for the presence and potency of immunogenic responses compared to responses induced by corresponding forms of non-amino acid substituted PE peptides, polypeptides, and fusion or conjugation constructs.

Assays for measuring immunogenicity of amino acid substituted forms of PE specifically (as indicated above), or PE molecules, generally, may also be done according to methods routinely used and well-known to those of skill in the art. For example, immunogenicity of amino acid substituted forms of PE, in particular, or PE molecules, in general, (as indicated above) may be measured in vivo in non-human primates and/or in transgenic mouse model systems.

Example 3: Measuring Biological Activity of Amino Acid Substituted Forms of PE

Assays for measuring the biological activity of amino acid substituted/deimmunized forms of PE, may be done according to methods routinely used and well-known to those of skill in the art. Measured biological activities of deimmunized (“DI”) forms of PE (“DI-PE”), in particular, or PE molecules, in general, may include, for example, assays to measure:

-   -   a) general or specific inhibition of protein synthesis (i.e.,         measuring inhibition of synthesis of a specific protein (or         specific proteins) or inhibition of overall (mass) protein         synthesis;     -   b) inhibition of translation elongation factor EF-2 biological         activity;     -   c) induction or catalysis of ADP-ribosylation of EF-2; and     -   d) eukaryotic cell killing activity (cell cytotoxicity).

Assays for Biological Activity: Inhibition of Protein Synthesis

In one example, measurement of inhibition of protein synthesis may be done via use of in vitro transcription/translation assays (which are routinely used and well-known to those of skill in the art). For example, a cell-free assay may be used to measure DI-PE induced inhibition of in vitro transcription/translation of a target plasmid (such as, but not limited to, T7-luc). In the case of using a T7-luc transcription/translation assay, the biological activity readout would be chemiluminescent measurement of luciferase activity wherein amino acid substituted forms of PE are compared to corresponding non-amino acid substituted forms of PE for ability/inability to inhibit translation of the luciferase enzyme in vitro. In such assays, the PE polypeptides being assayed can be introduced via expression from template DNA (e.g., a PCR product) encoding the toxin-conjugate gene, or by directly introducing quantified amounts of PE proteins. Such assays may be used to assess IC50 values* of the various forms of PE tested (*IC50=concentration at which 50% of protein synthesis is inhibited versus standardized control samples lacking PE).

Some examples of kits and reagents available for in vitro transcription/translation assays include, but are not limited to:

-   -   TNT® SP6 Coupled Reticulocyte Lysate System (e.g., PROMEGA®         catalog #L4610 (PROMEGA® Corp., Madison, Wis., USA)) allows for         eukaryotic cell-free protein expression in a single-tube, as a         coupled transcription/translation process. More traditional         rabbit reticulocyte lysate translations commonly use RNA         synthesized in vitro from SP6, T3 or T7 RNA polymerase promoters         and require three separate reactions with several steps between         each reaction. The TNT® System bypasses many of these steps by         incorporating transcription directly into the translation mix.         See e.g., PROMEGA® Technical Bulletin #TB126 (Revised         December 2010) which is incorporated by reference herein. See         also, Pelham et al., Eur. J. Biochem. 67, 247-56 (1976), Krieg         et al., (1984) Nucl. Acids Res. 12, 7057-7070 (1984). See also,         U.S. Pat. Nos. 5,324,637; 5,492,817; 5,641,641, and, 5,650,289.     -   TNT® T7 Quick Coupled Transcription/Translation System (e.g.,         PROMEGA® catalog #L1170 (PROMEGA® Corp., Madison, Wis., USA))         further simplifies in vitro transcription/translation reactions         by combining RNA polymerase, nucleotides, salts and Recombinant         RNasin® Ribonuclease Inhibitor with the reticulocyte lysate to         form a single TnT® Quick Master Mix. The TnT® Quick Coupled         Transcription/Translation System may be used with plasmids for         transcription and translation of genes cloned downstream from         either the T7 or SP6 RNA polymerase promoters. The TnT® Quick         System includes a luciferase-encoding control plasmid and         Luciferase Assay Reagent, which can be used in a non-radioactive         assay for rapid (<30 seconds) detection of functionally active         luciferase protein. Starting with either circular plasmid DNA or         PCR-generated DNA, in vitro transcription/translation results         may be obtained in 5-6 hours. See e.g., PROMEGA® Technical         Bulletin #TM045 (Revised May 2011) which is incorporated by         reference herein.     -   STEADY-GLO® Luciferase Assay System (e.g., PROMEGA® catalog         #E2510) (PROMEGA® Corp., Madison, Wis., USA)) allows for         high-throughput quantitation of firefly (Photinus pyralis)         luciferase expression in mammalian cells via batch processing of         96- and 384-well plates. The STEADY-GLO® Luciferase Assay System         provides signal half-lives of over 5 hours in commonly used cell         culture media without prior sample processing. Throughput rates         of several thousand samples per hour may be achieved with high         reproducibility under standard laboratory conditions. See e.g.,         PROMEGA® Technical Bulletin #TM051 (Revised March 2009 & Revised         September 2011) which is incorporated by reference herein. See         also, U.S. Pat. Nos. 5,641,641; 5,650,289; 5,583,024; 5,674,713;         and 5,700,673.

Full protocols for use of such kits are provided by the manufacturer with each kit. A brief example of a typical experimental procedure may include:

-   -   Assembling kit reagents (except target T7-luc plasmid), plus PE         test samples (using an experimentally determined titration of PE         test samples; e.g., in a range of 0-500 ng DNA per reaction for         PCR templates or using a PE protein titre in a range to be         determined experimentally), in a total volume of 12.5 ul         RNAse-free water in PCR tubes or cell wells on plates.     -   For plasmid DNA: Pre-incubate for required time (e.g. 30-60 min,         time to be determined experimentally) at 30° C. to allow         pre-reaction transcription/translation to occur.     -   For purified protein: No pre-incubation step required.     -   Add target plasmid T7-luc (e.g. 250 ng/reaction, determined         experimentally) and incubate further (e.g. 30-60 min, time to be         determined experimentally) at 30° C.     -   Stop reaction by placing on ice. Increase sample volume to 50 ul         with RNAse-free water.     -   Add luciferase reagent (e.g. SteadyGlo, 50 ul per well) to each         well, incubate according to manufacturer's instructions,         transfer to 96 well black/white plate and read chemiluminescent         signal via chemiluminescence platereader.     -   Compare to ‘zero toxin’ control samples (i.e., no PE present) to         determine the % inhibition of transcription/translation (i.e.,         as a function of inhibition of luciferase activity).     -   Compare inhibition of transcription/translation values of amino         acid substituted/deimmunized forms of PE compared to         corresponding forms of non-amino acid substituted PE.

Comparative protein synthesis inhibition values may show that various forms of DI-PE exhibit 100% or about 100% of biological activity (inhibition of protein synthesis) compared to corresponding forms of non-amino acid substituted PE. Comparative protein synthesis inhibition values may also show that various forms of DI-PE exhibit at least 95%, or at least about 95%, at least 90%, at least about 90%, at least 85%, at least about 85%, at least 80%, at least about 80%, at least 75%, at least about 75%, at least 70%, at least about 70%, at least 60%, at least about 60%, at least 50%, or at least about 50% of biological activity compared to corresponding forms of non-amino acid substituted PE.

Assays for Biological Activity: Cell Cytotoxic Activity

In one example, measurement of cell cytotoxic activity may be done via use of in vitro cell based assays wherein deimmunized PE (DI-PE)-antibody conjugates are assayed in comparison to non-amino acid substituted PE-antibody conjugates. The antibody portion of such conjugates would be antibodies, or antigen-binding fragments thereof which specifically bind antigens expressed on the cell-surface of cell types used in such in vitro assays. Cell cytotoxicity may be quantitated, for example, by measuring cell lysis wherein the biological readout is represented by measurement of, for example, based on chemiluminescent (LUMI), fluorometric (FL), and colorimetric (COL) outputs; such as can be practiced using commercially available kits routinely used and well-known to those of skill in the art.

Some examples of kits available for measurement and comparison of DI-PE versus non-amino acid substituted PE cell cytotoxicity include, without limitation:

-   -   TOXILIGHT® BioAssay Kit (e.g., Catalog ##LT07-117 (Lonza         Rockland, Inc., Rockland, Me., USA)) is a non-destructive         bioluminescent cytotoxicity assay that quantitatively measures         release of Adenylate Kinase (AK) from damaged mammalian cells         and cell lines in vitro. The assay is based on the         bioluminescent measurement of AK which is present in all cells.         A loss of cell integrity, through damage to the plasma membrane,         results in the leakage of a number of factors from cells         cultured in vitro into the surrounding medium. The measurement         of the release of AK from the cells allows the accurate and         sensitive determination of cytotoxicity and cytolysis. The         reaction involves two steps. The first involves the addition of         ADP as a substrate for AK. In the presence of the enzyme, AK,         the ADP is converted to ATP for assay by bioluminescence. The         bioluminescent part of the assay utilizes the enzyme Luciferase,         which catalyses the formation of light from ATP and luciferin.         By combining these two reactions, the emitted light intensity is         linearly related to the AK concentration and can be measured         using a luminometer or beta counter. See, “TOXILIGHT® BioAssay         Kit: Instructions for Use,” ©2007 Lonza Rockland, Inc., which is         incorporated by reference herein. See also, Crouch, et al., J.         Immunol. Methods, 160(1):81-88 (1993); Olsson, T. et al., J.         Appl. Biochem 5, 347-445 (1983); and, Squirrell et al., A         Practical Guide to Industrial Uses of ATP Luminescence in Rapid         Microbiology, p. 107-113 (1997).     -   CYTOTOX-GLO® (e.g., PROMEGA® catalog #G9290 (PROMEGA® Corp.,         Madison, Wis., USA)) is a luminescent cytotoxicity assay that         measures the relative number of dead cells in cell populations.         The assay measures extracellular activity of a distinct         intracellular protease activity (dead-cell protease) when the         protease is released from membrane-compromised cells. A         luminogenic cell-impermeant peptide substrate         (AAF-aminoluciferin) is used to measure dead-cell protease         activity. The liberated aminoluciferin product is measured as         “glow type” luminescence generated by ULTRA-GLO™ Recombinant         Luciferase provided in the assay reagent. The AAF-aminoluciferin         substrate cannot cross the intact membrane of viable cells and         does not generate appreciable signal from the live-cell         population. The amount of luminescence directly correlates with         the percentage of cells undergoing cytotoxic stress. With the         addition of a lysis reagent (provided with the kit), the         CYTOTOX-GLO™ Assay provides a luminescent signal associated with         the total number of cells in each assay well. Viability can be         calculated by subtracting the luminescent dead-cell signal from         the total luminescent value, thus allowing normalization of         assay data to cell number and mitigation of assay interferences.         The cytotoxicity protease biomarker is constitutive and         conserved across cell lines. See e.g., PROMEGA® Technical         Bulletin Nos. TB359 (Revised May 2009 & Revised October 2011)         which is incorporated by reference herein. See also, Niles, A.         et al. (2007) Anal. Biochem., 366, 197-206 (2007) and U.S. Pat.         Nos. 6,602,677 and 7,241,584.     -   CYTOTOX-ONE™ kit (e.g., PROMEGA® catalog #G7891 (PROMEGA® Corp.,         Madison, Wis., USA)) allows performance of homogeneous membrane         integrity assays wherein a fluorometric method may be used to         estimate the number of nonviable cells present in multiwell         plates. This assay measures the release of lactate dehydrogenase         (LDH) from cells with damaged membranes. LDH released into the         culture medium is measured with a coupled enzymatic assay that         results in the conversion of resazurin into a fluorescent         resorufin product. The amount of fluorescence produced is         proportional to the number of lysed cells (which may be         monitored using a 96- or 384-well plate formats). The         CYTOTOX-ONE™ Reagent does not damage normal healthy cells.         Therefore, reactions to measure released quantities of LDH can         be performed directly in a homogeneous format in assay wells         containing a mixed population of viable and damaged cells. See         e.g., PROMEGA® Technical Bulletin #TB306 (Revised May 2009)         which is incorporated by reference herein. See also, U.S. Pat.         Nos. 6,982,152 and 7,282,348.     -   CELLTITER GLO® Luminescent Cell Viability Assay (e.g., PROMEGA®         catalog #G7571 (PROMEGA® Corp., Madison, Wis., USA)) provides a         homogeneous method for determining the number of viable cells in         a culture based on quantitation of the amount of ATP present (an         indicator of metabolically active cells). The CELLTITER GLO®         Assay is particularly useful for automated high-throughput         screening (HTS), cell proliferation and cytotoxicity assays. The         homogeneous assay procedure involves adding the single reagent         (CELLTITER GLO® Reagent) directly to cells cultured in         serum-supplemented medium. The assay allows for detection of as         few as 15 cells/well in a 384-well format in 10 minutes after         adding reagent and mixing. The homogeneous “add-mix-measure”         format results in cell lysis and generation of a luminescent         signal proportional to the amount of ATP present (which is         directly proportional to the number of cells present in         culture). The CellTiter-Glo® Assay generates a “glow-type”         luminescent signal, which has a half-life generally greater than         five hours, depending on cell type and medium used. See e.g.,         PROMEGA® Technical Bulletin Nos. TB288 (Revised June 2009 &         Revised August 2011) which are incorporated by reference herein.         See also: U.S. Pat. Nos. 6,602,677; 7,241,584; 7,700,310;         7,083,911; 7,452,663; 7,732,128; 7,741,067; 5,583,024,         5,674,713; and 5,700,673.     -   VIALIGHT® Plus Kit (e.g., Catalog ##LT07-221 (Lonza Rockland,         Inc., Rockland, Me., USA)) may be used for rapid detection of         cytotoxicity in mammalian cells and cell lines in culture via         determination of ATP levels. Any form of cell injury results in         a rapid decrease in cytoplasmic ATP levels. Therefore, the         VIALIGHT® Plus Kit may be used to measure a wide range of         biological activities effecting cell viability. The kit is         formulated for use with a microtitre plate reading luminometer         for assay automation. The assay is based on bioluminescent         measurement of ATP is present in all metabolically active cells.         The bioluminescent method utilizes an enzyme, Luciferase, which         catalyses the formation of light from ATP and luciferin         according to the following reaction:         ATP+Luciferin+O2−Luciferase/Mg²⁺→Oxyluciferin+AMP+PPi+CO₂+LIGHT     -   The emitted light intensity is linearly related to the ATP         concentration and can be measured using a luminometer or beta         counter. The assay is conducted at ambient temperature (18°         C.-22° C.), the optimal temperature for luciferase enzymes. See,         “VIALIGHT® Plus Kit: Instructions for Use,” ©2007 Lonza         Rockland, Inc, which is incorporated by reference herein.

Full protocols for use of such kits are provided by the manufacturer with each kit. A brief example of a typical experimental procedure may include:

-   -   Plate cells to test plate (e.g., 96 well plates) in growth         medium.     -   Incubate cells with titrations of amino acid substituted forms         of PE-toxin conjugates (including zero toxin and non-amino acid         substituted PE controls (up to a maximum toxicity point, e.g.         100% cell lysis) for required time (determined experimentally,         e.g. 48-72 hr).     -   Add kit reagents for cytotoxicity measurements as per         manufacturer's instructions.     -   Transfer test samples to 96 well black/white walled plate (as         appropriate) and read reaction signal output.     -   Compare cell cytotoxicity values obtained for         substituted/deimmunized forms of PE versus corresponding         non-amino acid substituted forms of PE.

Comparative cell cytotoxicity values may show that various forms of DI-PE exhibit 100% or about 100% of biological activity (induction of cell cytotoxicity) compared to corresponding forms of non-amino acid substituted PE. Comparative cell cytotoxicity values may also show that various forms of DI-PE exhibit at least 95%, or at least about 95%, at least 90%, at least about 90%, at least 85%, at least about 85%, at least 80%, at least about 80%, at least 75%, at least about 75%, at least 70%, at least about 70%, at least 60%, at least about 60%, at least 50%, or at least about 50% of biological activity compared to corresponding forms of non-amino acid substituted PE.

Example 4: Measuring Ability of Deimmunized PE Variants to Inhibit Protein Synthesis

Quantitative in vitro transcription/translation (IVTT) assays to assess the biological activity of deimmunized variants of PE in inhibiting protein synthesis (i.e., possess wild-type PE biological activity) may be performed using the TNT® Quick Coupled Transcription/Translation Systems assay from PROMEGA® Corp. (Madison, Wis., USA). See, PROMEGA® Technical Bulletin #TB126 (Revised December 2010) which is incorporated by reference herein.

Example 5: Measuring Ability of a PE-IL2 Fusion Protein to Inhibit Protein Synthesis in an In Vitro Transcription/Translation (IVTT) Assay

A preliminary experiment was performed to compare the ability of a PE-IL2 fusion protein to inhibit protein synthesis in an in vitro transcription/translation assay when a commercially available PE-IL fusion protein is translated in vitro following transcription from either a circular plasmid expression vector or a linearized plasmid expression vector. The PE-IL2 expression vector in this experiment is referred to as “VVN-52431.” A few examples of IL2-PE fusion construct are shown in SEQ ID NO:164, 165 and 166. The aim of this experiment was to determine if circular or linearized plasmids produced significantly different quantities of PE-IL protein in the PROMEGA® Corp. TNT® Quick Coupled Transcription/Translation Systems assay. A commercially available T7 Promoter/Luciferase expression vector (PROMEGA® Corp.; hereinafter “T7-Luc DNA”) was used to measure the ability of PE-IL2 to inhibit protein synthesis in vitro.

Based on a pilot IVTT experiment, it was determined that 0.2 μg T7-Luc DNA provided optimal RLU (Relative Light Units) in a 90 minute IVTT reaction. In this experiment, VVN-52431 was linearized using the restriction enzyme Fsp-I. Linearized and circular VVN-52431 DNA were used as templates in the IVTT reactions. Reactions were done in triplicate, using 0.5, 1 and 2 μg of DNA. The T7 control reaction was performed using 1 μg DNA. Reactions were analyzed via SDS-PAGE and by Luciferase assay.

Materials:

Item Vendor Lot # Nuclease-free water (1000 ml) Ambion 1105062 TNT T7 Quick Coupled T/T system PROMEGA ® 328577 T7 luciferase plasmid DNA (From PROMEGA ® same kit) Fsp I NEB 0571101 Dual Glo ® Luciferase Assay PROMEGA ® 322310 System Ultrapure Water GIBCO 896656 Tris-Glycine SDS Sample Buffer, Invitrogen 743995 2x 10x Reducing Agent Invitrogen 897034 Criterion Tris HCl 4-15%, 1 mm, Bio-Rad 400059499 12 + 2 well Precision Plus Protein Standards, Bio-Rad 310009928 Kaleidoscope 10x Tris/Glycine/SDS Buffer Bio-Rad 210007884 Gelcode Blue Safe Protein Stain ThermoFisher LL152043

Equipment:

Item Vendor ID # P20, P200, P1,000 Rainin N/A Water bath Luminometer Power Pac HC Bio-Rad N/A Heat block VWR N/A Microcentrifuge, refrigerated Eppendorf N/A Platform Adjustable Tilt Rocker Labnet N/A Thermal cycler MJ Research N/A

Procedure:

Per manufacturer's instructions: Except for the actual transcription/translation incubation, all handling of the TNT® Quick Master Mix was performed at 4° C. Unused Master Mix was refrozen as soon as possible after thawing to minimize loss of translational activity.

Restriction Digest:

In PCR tubes, the following were combined:

VVN-52431 was linearized by combining the following:

NF H₂O VVN52431 Fsp I Reaction Rxn (μL) (μL) dig. final Product 1 5 5 (5 μg) 0 0.5 μg/μl Circular Vector - No Restriction enzyme added 2 4 5 (5 μg) 1 0.5 μg/μl Linearized Vector

Reactions were incubated at 37° C. for 60 min.

Reactions were heat inactivated at 65° C. for 20 min.

IVTT Reactions;

-   -   1. In nuclease-free 1.5 ml eppendorf tubes, the following were         combined according to the chart below:         -   Diluted T7-Luc DNA in NF (nuclease free) water at 1:5. Final             DNA concentration=0.1 μg/μl.         -   Serial diluted unlinearized and linearized VVN-52431 DNA             (0.5 μg/μl) in NF water at 1:5. Final concentration=0.5             μg/μl, 0.1 μg/μl, 0.02 μg/μl.

NF T7 Luc Methi- T7 TNT H₂O DNA VVN52431 Fsp onine rex Rxn (μL) (μL) (μL) I dig. (μL) (μL) 1 7 2 (0.2 μg) 1 40 2 7 2 (1 μg) − 1 40 3 7 2 (1 μg) + 1 40 4 5 2 (0.2 μg) 2 (1 μg) − 1 40 5 5 2 (0.2 μg) 2 (0.2 μg) − 1 40 6 5 2 (0.2 μg) 2 (0.04 μg) − 1 40 7 5 2 (0.2 μg) 2 (1 μg) + 1 40 8 5 2 (0.2 μg) 2 (0.2 μg) + 1 40 9 5 2 (0.2 μg) 2 (0.04 μg) + 1 40 10 9 1 40

-   -   2. Reactions were incubated at 30° C. for 90 minutes in a water         bath.     -   3. Reactions were analyzed for the synthesis of functional         Luciferase using a standard Luciferase assay.

Luciferase Assay:

-   -   1. Luciferase assay substrate was prepared according to         manufacturer's instructions:         -   Reagent Kit was thawed at room temperature.         -   Dual-Glo® Luciferase Buffer was transferred into the             Dual-Glo® Luciferase Substrate bottle and shaken slightly to             ensure the substrate dissolved.         -   Dual-Glo® Stop & Glo® substrate was transferred into the             Dual-Glo® Stop & Glo® buffer and mixed well.         -   Rehydrated reagent was aliquoted into 15 ml centrifuge tube             (10 ml/tube) and wrapped with Aluminum foil.         -   Rehydrated reagent was stored at −80° C. until ready for use             (the reagent is good for 6 months).     -   2. 5 μl of reaction end products/well were transferred into a         96-well white plate     -   3. 100 μL of the Luciferase Assay Reagent was dispensed per well         and mixed by pipetting 2-3×.     -   4. RLU's for each well on plate were read within 10 minutes.

Results:

Results are shown in FIG. 9. Circular plasmid expression vector encoding PE-IL2 fusion protein was slightly better at inhibiting Luciferase protein synthesis compared to linearized plasmid encoding the same (at all Luciferase vector:VVN-52431 vector ratios). These results also demonstrate the ability of to test and compare the biological activity of PE-fusion proteins in inhibiting protein synthesis.

In addition to measuring inhibition of protein synthesis as a measure of light production catalyzed by Luciferase, quantitative analysis of inhibition of protein synthesis was also performed by separating polypeptide reaction products on SDS-PAGE gels, staining, and assessing amounts of polypeptide produced (data not shown).

Assays such as these may be used to compare the ability of amino acid substituted (e.g., deimmunized) forms of PE (alone or as fusion proteins) to retain biological activity (such as inhibition of protein synthesis) compared to corresponding non-amino acid substituted forms of PE (alone or as fusion proteins).

Example 6: In Vitro Transcription/Translation (IVTT) Assay to Measure and Compare Ribosylation Activity of Amino Acid Substituted Variants of PE

Purpose: This protocol provides an example of they type of methods which may be used to measure and compare the ribosylation activity (i.e., inhibition of protein synthesis) of amino acid substituted forms of PE compared to corresponding non-amino acid substituted forms of PE.

Background:

The IVTT assay measures PE mediated inhibition of in vitro transcription/translation of a target plasmid, T7-Luc. The level of inhibition (or lack thereof) is determined by chemiluminescent measurement of Luciferase activity (i.e., the transcribed and translated protein). In this assay, a lowered level of transcription and translation (and thereby, lowered levels of chemiluminescent light output) corresponds to increased inhibition of protein synthesis, IVTT can be performed using template DNA encoding PE, or by directly using quantified protein. This assay may be used to rank different PE variants against each other and to compare their biological activities to corresponding non-amino acid substituted forms.

Materials:

Test sample: Vectors comprising either circular plasmids with an SP6 promoter or linearized plasmids with a T7 promoter.

Reagents and Materials Vendor Nuclease-free water (1000 ml) Ambion TNT SP6 Quick Coupled T/T system PROMEGA ® SP6 luciferase plasmid DNA (From PROMEGA ® same kit) RNase-free 1.5 ml microfuge tubes Ambion Dual Glo ® Luciferase Assay System PROMEGA ®

Equipment:

Item Vendor P20, P200, P1,000 Rainin 96 well white plate Costar Water bath (circulation) Luminometer Microcentrifuge, refrigerated Eppendorf

Reagent Preparation:

Luciferase Preparation:

-   -   1. Thaw reagent Kit on ice or at 4 degrees C.     -   2. Transfer entire Dual-Glo® Luciferase Buffer into Dual-Glo®         Luciferase Substrate bottle and shake bottle slightly to ensure         substrate completely dissolved.     -   3. Transfer entire Dual-Glo® Stop & Glo® substrate into         Dual-Glo® Stop & Glo® buffer and mix well.     -   4. Aliquot rehydrated reagent into 15 ml centrifuge tube (10         ml/tube) and wrap tube with Aluminum foil.     -   5. Store rehydrated reagent in −80° C. Freezer (reagent is good         for 6 months)

Procedure:

Per manufacturer's recommendations: Except for the actual transcription/translation incubation, all handling of TNTR Quick Master Mix should be done at 4° C. Any unused Master Mix should be refrozen as soon as possible after thawing to minimize loss of translational activity. Do not freeze-thaw the Master Mix more than two times.

Plasmid DNA Dilution:

Dilute plasmid DNA and Luc plasmid DNA in nuclease free water to final concentration of 0.1 μg/μl.

IVTT Reactions

-   -   1. In 1.5 ml NF (nuclease free) eppendorf tubes, the following         are combined for each test sample:         -   a. 5 μL of NF H₂O;         -   b. 2 μl, 0.1 μg/μl test plasmid (for increased accuracy of             results test a dilution series of samples);         -   c. 1 μl, 1 mM Methionine;         -   d. 40 μL TNT quick master mix;         -   e. Negative control (reaction mix only, NF water 9 μl,             methionine 1 μl, reaction mixture 40 μl;     -   2. Incubate reaction mixes at 30° C. for 15 minutes in water         bath;     -   3. Add 2 μl, 0.1 μg/μl Luc plasmid to each reaction mix;     -   4. Incubate reactions at 30° C. for 90 minutes in water bath;         and     -   5. Transfer all samples onto ice to stop reaction.

Luciferase Assay

-   -   6. Transfer 5 μl of end product/well into 96-well white plates         in triplicate;     -   7. Dispense 100 μL of Luciferase Assay Reagent per well. Mix by         pipetting 2-3×;     -   8. Read entire plate within 10 minutes.

Calculations

-   -   1. Calculate percent inhibition based on relative luminescence         units (RFU) of the test sample divided by the RFU of the LUC         plasmid with no test sample, then subtract the result from 100.     -   2. Calculate the percent of activity of non-amino acid         substituted PE by percent inhibition of the test sample divided         by the percent inhibition of non-amino acid substituted, then         multiply the result by 100.     -   3. If a dilution series of samples is tested, calculate the IC50         (half maximal inhibition concentration) for each sample using         the RFU of the test sample divided by the RFU of the LUC plasmid         alone, then subtract the result from 100. Determine the         concentration which results in 50% inhibition.     -   4. Calculate the percent of non-amino acid substituted PE         inhibition by dividing the IC50 of the non-amino acid         substituted PE by the IC50 of the test sample and multiplying         the result by 100.

Example 7: Ex Vivo Assays to Assess Immunogenicity of Amino Acid Substituted Forms of PE (i.e. Deimmunized PE) Versus Corresponding Non-Amino Acid Substituted Forms

The immunogenicity of amino acid substituted forms of PE (alone or as PE-fusion proteins) are assessed using methods well-known and routinely used by those skilled in the art. For example, ELISA assays are used wherein serum is assayed ex vivo (following extraction from organisms in which amino acid substituted forms of PE, or non-amino acid substituted PE, (alone or as fusion proteins) are administered) to determine whether or not antibodies that specifically bind the administered protein are produced. It is noted that in the case of PE-fusion proteins it is necessary to use, as the ELISA assay target antigen, not only intact PE-fusion proteins (i.e., amino acid substituted or non-amino acid substituted PE), but to also test the PE component and the polypeptide fusion component separately to determine whether or not antibodies produced specifically bind the PE portion or the fusion polypeptide portion (e.g., IL2 as used in a previous example of a PE-IL2 fusion protein). Accordingly, it is most desirable to identify amino acid substituted forms of PE which do not result in host production of antibodies that specifically bind modified forms of PE (i.e., deimmunized forms of PE).

Organisms in which amino acid substituted forms of PE may be administered (alone or as fusion proteins) include, for example, without limitation: mice (including transgenic mice expressing human immunoglobulin genes), rats, rabbits, dogs, goats, sheep, horses, cows (and other bovine species), non-human primates, and humans.

Example 8: In Vitro and In Vivo Assays to Assess Cytotoxicity of Amino Acid Substituted Forms of PE

The cytotoxicity of amino acid substituted forms of PE (alone or as PE-fusion proteins) are assessed using methods well-known and routinely used by those skilled in the art. For example, the cytotoxic effects of amino acid substituted forms of PE (alone or as PE-fusion proteins) administered to cells in vitro or organisms in vivo, may be assessed with reference to cytotoxic (cell killing) effects on target cells, organs, tissues, or tumors against which PE or PE fusion proteins are expected to produce a cytotoxic effect. For example, the therapeutically beneficial cytotoxic effects of amino acid substituted PE-Mesothelin fusions may be assessed by monitoring and measuring reduction or elimination of tumor or cancer cells or tissues (in vitro or in vivo) in response to administration of amino acid substituted forms of PE-Mesothelin versus wild-type PE-Mesothelin fusion.

Organisms in which amino acid substituted forms of PE may be administered (alone or as fusion proteins) include, for example, without limitation: mice (including transgenic mice expressing human immunoglobulin genes), rats, rabbits, dogs, goats, sheep, horses, cows (and other bovine species), non-human primates, and humans.

Examples 9-13: Oligonucleotides Referenced in the Following Examples are Listed in Table 12 Example 9: Generation of cDNAs Encoding Amino Acid Substituted Forms of PE

The Kozak sequence in vector pET14b (EMD Millipore catalog #69660, Darmstadt, Germany) was modified by introducing a linker made up of annealed oligonucleotides 5′-CATGGTGGCTCTCCTTCTTAAAGTTAAACAAAATTATTT-3′ (SEQ ID NO:239)(OL2216 in Table 12) and

5′-CTAGAAATAATTTTGTTTAACTTTAAGAAGGAGAGCCAC-3′ (SEQ ID NO:240)(OL2217 in Table 12) (underlined letters indicate nucleotides changed in the Kozak sequence*) via NcoI and XbaI restriction sites into vector pET14b resulting in a modified Kozak sequence (SEQ ID NO:176) by mutation of three nucleotides at positions 587 to 589. The resulting vector was named pET14b-K.

Kozak sequence=(gcc)gccRccAUGG (SEQ ID NO:286), where R is a purine (i.e., adenine or guanine) three bases upstream of the start codon (AUG), which is followed by another ‘G’. See, Kozak, Nucleic Acids Res. 15 (20): 8125-8148 (1987).

Oligonucleotides for generation of genes encoding amino acid substituted forms of PE are listed as OL2164 to OL2194 and OL2281 to OL2366 in Table 12. A wild-type (WT) PE gene (SEQ ID NO:1) was made by gene synthesis and amplified using oligonucleotides: 5′-ATTGTCCATATGCCAGAAGGCGGTAGCCTGGC-3′ (SEQ ID NO:215)(OL2154 in Table 12) to introduce a NdeI site, and

-   -   5′-ATCCTCGAGTTACTTCAGGTCCTCACGCGGCG-3′ (SEQ ID NO:222)(OL2167 in         Table 12) to introduce a XhoI site. The resulting DNA fragment         was subcloned into pGEMT®-T (PROMEGA® catalogue #A1360,         PROMEGA®, Southampton, UK). Colonies were screened by PCR using         M13 primers OL0001 and OL0002 (Table 12). Subsequently the         wild-type (WT) PE gene was subcloned into pET14b-K using NdeI         and XhoI restriction enzymes (Fermentas catalog #FD0583 and         FD0695, respectively) and resulting in a gene encoding an         N-terminal His6 tag fused to the WT PE sequence. The resulting         vector was named pET14b-K-WT PE.

Oligonucleotides for generation of genes encoding amino acid substituted forms Genes encoding amino acid substituted forms of PE were generated using overlapping PCR with the WT PE gene in pET14b-K as template. Pairs of primers from the oligonucleotides of Table 12 (as noted in the “application” column of Table 12) were annealed to WT PE DNA and the amino acid substituted genes were PCR amplified using terminal oligonucleotides: 5′-ATCTCCCTCTAGAAATAATTTTGTTTAACTTTAAGAAG-3′ (SEQ ID NO:241)(OL2268 in Table 12) and

-   -   5′-ATCCTCGAGTTACTTCAGGTCCTCACGCGGCG-3′ (SEQ ID NO:216)(OL2161 in         Table 12). PCR fragments were and cloned into pET14b-K using         XbaI and XhoI restriction sites.

TABLE 12 Oligonueleotides Name sequence length application OL  001 CGCCAGGGTTTTCCCAGTCAC 24 M13 FOR GAC (SEQ ID NO: 205) OL  002 AGCGGATAACAATTTCACACA 24 M13 REV GGA (SEQ ID NO: 206) OL 2043 GAAGTGCAGCTGGTGGAG 18 RFB4 VH5′ PCR primer (SEQ ID NO: 207) sequence OL 2044 CAGAGCCACCTCCGCCTGAAC 49 RFB4 VH3 PCR primer CGCCTCCACCTGAGGAGACA sequence GTGACCAG (SEQ ID NO: 208) OL 2045 CAGGCGGAGGTGGCTCTGGC 50 RFB4 VK 5′ PCR Primer GGTGGCGGATCGGATATCCA Sequence GATGACCCAG (SEQ ID NO: 209) OL 2046 TTTGATCTCCAGCTTGGTG 19 RFB4 VK 3′ PCR Primer SEQ ID NO: 210) sequence OL 2047 CCCAGCCGGCCATGGCGGAA 35 RFB4 Pull through Primer GTGCAGCTGGTGGAG (SEQ ID (FOR)) NO: 211) OL 2048 GGTGCTCGAGTGCGGCCGCCC 41 RFB4 Pull through Primer GTTTGATCTCCAGCTTGGTG (REV) (SEQ ID NO: 212) OL 2097 AACCGCCCGGCCGTTCTTCTC 39 IEX02 GroEL/ES REV CGTGTTGCCCGGAAAGCC (SEQ ID NO: 213) OL 2098 GGGCCAAAGCTTGTTCTTGTT 36 IEX02 GroEL/ES FOR TGAGTCCACTCATGG (SEQ ID NO: 214) OL 2154 ATTGTCCATATGCCAGAAGGC 32 IEX02 PE38 FOR, GGTAGCCTGGC (SEQ ID introducing Ndel NO: 215) OL 2161 ATCCTCGAGTTACTTCAGGTC 32 IEX02 PE38 REV, CTCACGCGGCG (SEQ ID introducing XhoI NO: 216) OL 2162 GGGTGGTCGCCTGGACACTAT 30 IEX02 PE38 NM E229D CCTGGGTTG (SEQ ID NO: 217) FOR OL 2163 CAACCCAGGATAGTGTCCAG 30 IEX02 PE38 NM E229D GCGACCACCC (SEQ ID REV NO: 218) OL 2164 CAGTACGATAGAAACCCGGC 40 IEX02 PE38 S253N AGATTGCTGCGCGGTACGTA (SEQ ID NO: 219) OL 2165 CAGTACGATAGAAACCCGGC 40 IEX02 PE38 S253K AGCTTGCTGCGCGGTACGTA (SEQ ID NO: 220) OL 2166 CAGTACGATAGAAACCCGGC 40 IEX02 PE38 S253P AGAGGGCTGCGCGGTACGTA (SEQ ID NO: 221) OL 2167 CAGTACGATAGAAACCCGGC 40 IEX02 PE38 S253T AGGGTGCTGCGCGGTACGTA (SEQ ID NO: 222) OL 2168 GTACGTGCTCGTAGCAGAGAC 33 IEX02 PE38 Q206R CTGGATGCCATC (SEQ ID NO: 223) OL 2169 GATGGCATCCAGGTCTCTGCT 33 IEX02 PE38 Q206R ACGAGCACGTAC (SEQ ID NO: 224) OL 2170 CGTAGCCAGGACCTGAAGGC 33 1EX02 PE38 D209K CATCTGGCGTGGC (SEQ ID NO: 225) OL 2171 GCCACGCCAGATGGCCTTCAG 33 IEX02 PE38 D209K GTCCTGGCTACG (SEQ ID NO: 226) OL 2183 GAAGCTGCTCAGTCTGCCGTG 32 IEX02 PE38 I196A FOR, to TTCGGTGGCGT (SEQ ID pair with OL2161 NO: 227) OL 2184 ACGCCACCGAACACGGCAGA 32 IEX02 PE38 I196A REV, to CTGAGCAGCTTC (SEQ ID pair with OL2268 NO: 228) OL 2185 GAAGCTGCTCAGTCTAACGTG 32 IEX02 PE38 I196N FOR, to TTCGGTGGCGT (SEQ ID pair with OL2161 NO: 229) OL 2186 ACGCCACCGAACACGTTAGA 32 IEX02 P138 I196N REV, to CTGAGCAGCTTC (SEQ ID with OL2268 NO: 230) OL 2187 GGTGATGGCGGCGATGCCTCT 33 IEX02 to introduce I153A TTTTCTACCCGC (SEQ ID FOR NO: 231) OL 2188 GCGGGTAGAAAAAGAGGCAT 33 IEX02 to introduce I153A CGCCGCCATCACC (SEQ ID REV NO: 232) OL 2189 GGTGATGGCGGCGATACCTCT 33 IEX02 to introduce I1531 TTTTCTACCCGC (SEQ ID FOR NO: 233) OL 2190 GCGGGTAGAAAAAGAGGTAT 33 IEX02 to introduce I153T CGCCGCCATCACC (SEQ ID REV NO: 234) OL 2191 GGTGATGGCGGCGATCACTCT 33 IEX02 to introduce I153H TTTTCTACCCGC (SEQ ID FOR NO: 235) OL 2192 GCGGGTAGAAAAAGAGTGAT 33 IEX02 to introduce I153H CGCCGCCATCACC (SEQ ID REV NO: 236) OL 2193 GCACCCAGAACTGGAGAGTT 32 IEX02 to introduce T164R GAACGTCTGCTG (SEQ ID FOR NO: 237) OL 2194 CAGCAGACGTTCAACTCTCCA 32 IEX02 to introduce T164R GTTCTGGGTGC (SEQ ID REV NO: 238) OL 2216 CATGGTGGCTCTCCTTCTTAA 39 IEX02 Linker to optimize AGTTAAACAAAATTATTT Kozak in pET14b, to anneal (SEQ ID NO: 239) with OL2217 OL 2217 CTAGAAATAATTTTGTTTAAC 39 IEX02 Linker to optimize TGGAAGAAGGAGAGCCAC Kozak in pET14b, to anneal (SEQ ID NO: 240) with OL2216 OL 2268 ATCTCCCTTCTAGAAATAATTIT 38 IEX02 outside FOR spanns TGTTTAACTTTAAGAAG (SEQ over XbaI site (pET14b)-to ID NO: 241) be paired with OL2161 OL 2279 GAAGCTGCTCAGTCTATCGTG 32 IEX02 FOR oligo to remove TTCGGTGGCGT (SEQ ID TM to be paired with NO: 242) OL2161 OL 2280 ACGCCACCGAACACGATAGA 32 IEX02 REV oligo to CTGAGCAGCTTC (SEQ ID remove TM to be paired NO: 243) with 0L2268 OL 2281 CTCTGCTACGAGCACGGGCGC 32 IEX02 A201 REV, ONLY CACCGAACACG (SEQ ID for templates having Q206 NO: 244) OL 2282 CGTGTTCGGTGGCGCCCGTGC 32 IEX02 A201 FOR, ONLY TCGTAGCAGAG (SEQ ID for templates having Q206 NO: 245) OL 2283 CATCCAGGTCTCTGCTGGCAG 33 IEX02 A204 REV, ONLY CACGTACGCCAC (SEQ ID for templates having Q206 NO: 246) OL 2284 GTGGCGTAcurGcmccAGCA. 33 IEX02 A204 -FOR, ONLY GAGACCTGGATG (SEQ ID for templates having Q206 NO: 247) OL 2285 CATCCAGGTCTCTGCTCTGAG 33 IEX02 Q204 REV, ONLY CACGTACGCCAC (SEQ ID for templates having Q206 NO: 248) OL 2286 GTGGCGTACGTGCTCAGAGCA 33 IEX02 Q204 FOR, ONLY GAGACCTGGATG (SEQ ID for templates having Q206 NO: 249) OL 2287 CCAGTTCTGGGTGCCGGCGGT 31 IEX02 A158 REV AGAAAAAGAG (SEQ ID NO: 250) OL 2288 CTCTTTTTCTACCGCCGGCAC 31 IEX02 A158 FOR CCAGAACTGG (SEQ ID NO: 251) OL 2289 CCAGTTCTGGGTGCCCTGGGT 36 IEX02 Q158 REV AGAAAAAGAGATATC (SEQ ID NO: 252) OL 2290 GATATCTCTTTTTCTACCCAG 36 IEX02 Q158 FOR GGCACCCAGAACTGG (SEQ ID NO: 253) OL 2291 GTCCAGTTCTGGGTGGAGCGG 38 IEX02 S159 REV GTAGAAAAAGAGATATC (SEQ ID NO: 254) OL 2292 GATATCTCTTTTTCTACCCGCT 38 IEX02 S159 FOR CCACCCAGAACTGGAC (SEQ ID NO: 255) OL 2293 ACCACCCAGAACTGGACCGTT 25 IEX02 T159 REV GAAC (SEQ ID NO: 256) OL 2294 CCAGTTTCTGGGTGGTTGCGGGT 31 IEX02 717159 FOR AGAAAAAGAG (SEQ ID NO: 257) OL 2295 GAGCTTGGGTCCAGATCGCCA 23 IEX02 generic REV oligo CC (SEQ ID NO: 258) for mutations at 333 OL 2296 CTGGACCCAAGCTCTGCCCCG 31 IEX02 A333 FOR GATAAAGAAC (SEQ ID NO: 259) OL 2297 CTGGACCCAAGCTCTAACCCG 28 IEX02 N333 FOR GATAAAG (SEQ ID NO: 260) OL 2298 CTGGACCCAAGCTCTACCCCG 28 IEX02 1333 FOR GATAAAG (SEQ ID NO: 261) OL 2299 CTGGACCCAAGCTCTCAGCCG 31 IEX02 Q333 FOR GATAAAGAAC (SEQ ID NO: 262) OL 2300 CTGGACCCAAGCTCTCACCCG 28 IEX02 H333 FOR GATAAAG (SEQ ID NO: 263) OL 2301 CTGGACCCAAGCTCTATCCCG 48 IEX02 N338 FOR GATAAAGAAAACGCTATTTCT GCCCTG (SEQ ID NO: 264) OL 2302 CTGGACCCAAGCTCTATCCCG 46 IEX02 E338 FOR GATAAAGAAGAGGCTATTTCT GCCC (SEQ ID NO: 265) OL 2303 CTGGCTACGAGCACGGGCGC 28 IEX02 V201A REV CACCGAAC (SEQ ID NO: 266) OL 2304 GTTCGGTGGCGCCCGTGCTCG 28 IEX02 V201A FOR TAGCCAG (SEQ ID NO: 267) OL 2305 CTTCAGGTCCTGGCTGGCAGC 30 IEX02 R204A REV, ONLY ACGTACGCC (SEQ ID NO: 268) for templates having D209K OL 2306 GGCGTACGTGCTGCCAGCCAG 30 IEX02 R204A FOR, ONLY GACCTGAAG (SEQ ID NO: 269) for templates having D209K OL 2307 CTTCAGGTCCTGGCTCTGAGC 29 IEX02 R204Q REV, ONLY ACGTACGC (SEQ ID NO: 270) for templates having D209K OL 2308 GCGTACGTGCTCAGAGCCAG 29 IEX02 R204Q FOR, ONLY GACCTGAAG (SEQ ID NO: 271) for templates having D209K OL 2309 GTTCAACGGTCCAGTTGTTG 33 IEX02 Q161N REV TGCCGCGGGTAG (SEQ ID NO: 272) OL 2310 CTACCCGCGGCACCAACAACT 33 IEX02 Q161N fOR GGACCGTTGAAC (SEQ ID NO: 273) OL 2311 GTTTCAACGGTTCCAGTGGTGG 33 IEX02 Q161T REV TGCCGCGGGTAG (SEQ ID NO: 274) OL 2312 CTACCCGCGGCACCACCAACT 33 IEX02 Q161T FOR GGACCGTTGAAC (SEQ ID NO: 275) OL 2313 CAGCAGACGTTCAACGGCCC 31 IEX02 T164A REV AGTTCTGGGTG (SEQ ID NO: 276) OL 2314 CACCCAGAACTGGGCCGTTGA 31 IEX02 T164A FOR ACGTCTGCTG (SEQ ID NO: 277) OL 2315 GACGTTCAACGGTCCAGGCCT 33 IEX02 N162A REV GGGTGCCGCGGG (SEQ ID NO: 278) OL 2316 CCCGCGGCACCCAGGCCTGG 33 IEX02 N162A FOR ACCGTTGAACGTC (SEQ ID NO: 279) OL 2318 ATTGCCACCATGGCGGAAGTG 22 IEX02 FOR RFB4 (NcoI) C (SEQ ID NO: 280) OL 2320 CACCAGGCCGCTGCTTTTGAT 31 IEX02 REV to create RBF4 CTCCAGCTTG (SEQ ID for RFB4-PE38-8xHis to NO: 281) pair with OL2318 OL 2321 CAAGCTGGAGATCAAAAGCA 31 IEX02 FOR to create GCGGCCTGGTG (SEQ ID RFB4-PE38-8xHis to pair NO: 282) with OL2322 OL 2322 CGATTCTCGAGTTACTTCAGG 66 IEX02 REV introducing TCCTCGTGGTGGTGGTGATGA 8xHis C-terminus of PE, TGATGATGACGCGGCGGTTTA introducing XhoI CCC (SEQ ID NO: 283) OL 2323 CAAGCTGGAGATCAAAGCTC 44 IEX02 FOR to create ATGGGGGCAGCCATCATCATC RFB4-6xHis PE38 fusions ATC (SEQ ID NO: 284) (pIEX02-302 and pIEX02- 304) to pair with OL2161 OL 2324 GATGATGATGATGGCTGCCCC 44 IEX02 REV to create CATGAGCTTTGATCTCCAGCT RFB4-6xHis PE38 fusions TG (SEQ ID NO: 285) (pIEX02-302 and pIEX02- 304) to pair with OL2318

Example 10: Analysis of Genes Encoding Amino Acid Substituted Forms of PE by an In Vitro Transcription/Translation (IVTT) Assay

The cell-free in vitro transcription/translation (IVTT) assay was performed with a TnT® T7 Coupled Reticulocyte Lysate System (PROMEGA® catalog #L4610) following the procedure described in the User's Manual provided in the kit. See, PROMEGA®, Technical Bulletin #TB126, Revised December 2010, pp. 1-28 (2010) which is incorporated by reference herein.

WT PE in plasmid pET14b-K was used as standard on every plate and tested at concentrations ranging from 0.08 ng to 10 ng in a 12.5 microliter final volume reaction. All test samples were run in triplicate. DNAs encoding WT or amino acid substituted PE in plasmid pET14b-K were added to the IVTT reaction mix supplemented with NAD+ (final concentration 0.15 mM; Fisher Scientific catalog #BPE9746-212) and incubated at 30° C. for 15 min. Following a subsequent cooling step at 4° C. for 5 min, 250 ng of T7 Luciferase plasmid (Luciferase T7 control DNA supplied in the TnT® T7 Coupled Reticulocyte Lysate System) was added to each reaction and incubated at 30° C. for 90 min. The reaction was stopped by placing the samples on ice. Samples were analyzed using the STEADY-GLO® Luciferase Assay (PROMEGA® catalog #E2510) according to the protocol provided by the manufacturer. See, PROMEGA®, Technical Bulletin #TM051, revised September 2011, pp. 1-23 (2011) which is incorporated by reference herein. Luminescence was measured in a FLUOstar OPTIMA plate reader (BMG Labtech Ltd., Aylesbury, UK)

A representative result is shown in FIG. 10 which shows the results expressed in CPS (counts per second as read from the FLUOstar OPTIMA fluorescence plate reader) for luciferase activity from IVTT assays of genes encoding either WT PE (pIEX02-001 (SEQ ID NO:1)) or encoding amino acid substituted PE (pIEX02-228 (SEQ ID NO:177), pIEX02-244 (SEQ ID NO:178), pIEX02-246 (SEQ ID NO:179)); which were expressed as fusion proteins comprising a histidine polymer and a linker sequence preceding a sequence of WT PE or amino acid substituted PE; see, pIEX02-001 PE WT (SEQ ID NO:189 (DNA) and SEQ ID NO:190 (AA)), pIEX02-228 amino acid substituted PE (SEQ ID NO:193 (DNA) and SEQ ID NO:194 (AA)), pIEX02-244 amino acid substituted PE (SEQ ID NO:197 (DNA) and SEQ ID NO:198 (AA)), pIEX02-246 amino acid substituted PE (SEQ ID NO:201 (DNA) and SEQ ID NO:202 (AA)). See also, Table 13.

For the analysis of various amino acid substituted PEs, the potency of each mutated PE in inhibiting IVTT was expressed as relative inhibition exhibited via expression from 2.5 nanograms of DNA encoding amino acid substituted PE compared to expression from 2.5 nanograms WT PE DNA as shown in Table 13 (data expressed as % inhibition of IVTT for the DNA encoding amino acid substituted PE compared to wild-type PE). In order to identify “inhibitory” amino acid substituted PE polypeptides (i.e., genes encoding amino acid substituted forms of PE which inhibit IVTT), selected mutations in each T cell epitope as identified in Table 11 were initially tested using various combinations of epitope 5 mutations (e.g., corresponding to S241N, S241K, S241P and S241T in SEQ ID NO:1) along with mutations in either: epitope 4; epitopes 4 and 3; epitopes 4 and 1; epitopes 4 and 2; or, epitopes 4 and 6 (see, Table 13). For all combinations except those including amino acid substitutions in epitope 3 at I184 (SEQ ID NO:1; or, I196 in SEQ ID NO:2) (which produced 0% inhibition), one or more inhibitory PE polypeptides were identified (Table 13). (Note: “Inhibitory PE polypeptides” indicates amino acid substituted forms of PE which exhibit PE biological activity in the inhibition of IVTT). From structural analysis of PE, it was noted that residue I184 (SEQ ID NO:1; or, I196 in SEQ ID NO:2) (anchor residue 1, Table 11) was located within the active enzymatic site of PE. In view of this result, alternative mutations distal to the active site were sought at anchor residues 6 and 9 (V189 and R192 in SEQ ID NO:1; or, V201 and R204 in SEQ ID NO:2). Alternative epitope 3 mutations at V189 and R192 in SEQ ID NO:1 were tested in combination with other epitope mutations. These mutations confirmed that inhibitory PE polypeptides with epitope 3 mutations could also be generated (Table 13, pIEX02-173 to -248). A range of combinations of DNAs encoding multiple amino acid substituted forms of PE were tested progressively leading to a final analysis of mutations in four of six, five of six, and six of six identified immunogenic epitopes. See, Table 13, “Quadruplicates”, “Quintuplicates” and “Sextuplicates”. In this regard, quadruplicate epitope mutations were identified which exhibited IVTT inhibitory activity ranging from 0% to about 70%. Quintuplicate mutations were identified that exhibited IVTT inhibitory activity ranging from about 5% to about 35%. Sextuplicate mutations were identified that exhibited IVTT inhibitory activity ranging from about 5% to about 20%. It is also noted that multiple single, double, and triple epitope mutations also resulted in amino acid substituted forms of PE exhibiting PE biological activity in the inhibition of IVTT such that the percent (%) inhibitory activity ranged from 0% to 100% (or about 100%); see Table 13.

Three different “candidates” (i.e., amino acid substituted forms of PE or DNA constructs encoding the same) were selected for use as examples in performing subsequent experiments described further herein. In particular, additional experiments were performed using the sextuplicate AA substituted candidate pIEX02-244 (SEQ ID NO:178; see also. Table 13); which retained approximately 20% of the WT PE inhibitory activity. Likewise, additional experiments were also performed using the sextuplicate AA substituted candidate pIEX02-246 (SEQ ID NO:179; see also, Table 13) which retained approximately 8% of the WT PE inhibitory activity; and using the quintuplicate AA substituted candidate pIEX02-228 (SEQ ID NO:177; see also, Table 13) which retained approximately 36% of the WT PE inhibitory activity. These were expressed as fusion proteins comprising a histidine polymer and a linker sequence preceding a sequence of WT PE or amino acid substituted PE; see, pIEX02-001 PE WT (SEQ ID NO:189 (DNA) and SEQ ID NO:190 (AA)), pIEX02-228 amino acid substituted PE (SEQ ID NO:193 (DNA) and SEQ ID NO:194 (AA)), pIEX02-244 amino acid substituted PE (SEQ ID NO:197 (DNA) and SEQ ID NO:198 (AA)), pIEX02-246 amino acid substituted PE (SEQ ID NO:201 (DNA) and SEQ ID NO:202 (AA)). These AA substituted PE polypeptides, and DNA constructs encoding, them may be referenced herein as “228”, “244” or “246” using simply these three numbers, or using these numbers and a prefix or suffix included therewith.

Moreover, it is noted that in view of the highly cytotoxic nature of wild-type PE, IVTT inhibition activity (i.e., cytotoxicity) as low as about 5% (or higher) of WT (e.g., 8%, 20%, and 36%) in amino acid substituted forms of PE may provide a therapeutically effective polypeptide. See, for example, Thomas et al., “Abrogation of Head and Neck Squamous Cell Carcinoma Growth by Epidermal Growth Factor Receptor Ligand Fused to Pseudomonas Exotoxin Transforming Growth Factor α-PE38,” Clin. Cancer Res. 10:7079-7087 (2004); Siegall et al., “Cell-specific toxicity of a chimeric protein composed of interleukin-6 and Pseudomonas exotoxin (IL6-PE40) on tumor cells”, Mol. Cell. Biol. 10(6); 2443-2447 (1990); and, Weldon & Pastan, “A Guide to Taming a Toxin—Recombinant Immunotoxins Constructed From Pseudomonas Exotoxin A for the Treatment of Cancer”, FEBS Journal 278(23):4683-4700(2011).

Moreover, it is noted that in view of the highly cytotoxic nature of wild-type PE, IVTT inhibition activity (i.e., cytotoxicity) as low as about 5% (or higher) of WT (e.g., 8%, 20%, and 36%) in amino acid substituted forms of PE may provide a therapeutically effective polypeptide. See, for example, Thomas et al., “Abrogation of Head and Neck Squamous Cell Carcinoma Growth by Epidermal Growth Factor Receptor Ligand Fused to Pseudomonas Exotoxin Transforming Growth Factor α-PE38,” Clin. Cancer Res. 10:7079-7087 (2004); Siegall et al., “Cell-specific toxicity of a chimeric protein composed of interleukin-6 and Pseudomonas exotoxin (IL6-PE40) on tumor cells”, Mol. Cell. Biol. 10(6); 2443-2447 (1990); and, Weldon & Pastan, “A Guide to Taming a Toxin—Recombinant Immunotoxins Constructed From Pseudomonas Exotoxin A for the Treatment of Cancer”, FEBD Journal 278(23):4683-4700 (2011).

TABLE 13 Examples of Amino Acid Substituted Forms of PE and Associated Cell Cytotoxic Activity. Epitopes pIEX02 - Epitope Epitope Epitope Epitope Epitope Epitope % Inhibition changed ### 5 4 3 1 2 6 of IVTT Wild-Type (WT) 001 100.00 (WT) Single Substitutions 5 003 S241N 100.00 [S253N] 5 004 S241K 100.00 [S253K] 5 005 S241P 99.71 [S253P] 5 006 S241T 99.99 [S253T] Double Substitutions 4, 5 007 S241N Q194R 41.63 [S253N] [Q206R] 4, 5 008 S241K Q194R 69.51 [S253K] [Q206R] 4, 5 009 S241P Q194R 20.58 [S253P] [Q206R] 4, 5 010 S241T Q194R 21.44 [S253T] [Q206R] 4, 5 011 S241N D197K 99.88 [S253N] [D209K] 4, 5 012 S241K D197K 42.49 [S253K] [D209K] 4, 5 013 S241P D197K 74.87 [S253P] [D209K] 4, 5 014 S241T D197K 98.84 [S253T] [D209K] Triple Substitutions 3, 4, 5 015 S241N Q194R I184A 0.00 [S253N] [Q206R] [I196A] 3, 4, 5 016 S241K Q194R I184A 0.00 [S253K] [Q206R] [I196A] 3, 4, 5 017 S241P Q194R I184A 0.00 [S253P] [Q206R] [I196A] 3, 4, 5 018 S241T Q194R I184A 0.00 [S253T] [Q206R] [I196A] 3, 4, 5 019 S241N Q194R I184N 0.00 [S253N] [Q206R] [I196N] 3, 4, 5 020 S241K Q194R I184N 0.00 [S253K] [Q206R] [I196N] 3, 4, 5 021 S241P Q194R I184N 0.00 [S253P] [Q206R] [I196N] 3, 4, 5 022 S241T Q194R I184N 0.00 [S253T] [Q206R] [I196N] 3, 4, 5 024 S241K D197K I184A 0.00 [S253K] [D209K] [I196A] 3, 4, 5 027 S241N D197K I184N 0.00 [S253N] [D209K] [I196N] 3, 4, 5 028 S241K D197K I184N 0.00 [S253K] [D209K] [I196N] 3, 4, 5 029 S241P D197K I184N 0.00 [S253P] [D209K] [I196N] 3, 4, 5 030 S241T D197K I184N 0.00 [S253T] [D209K] [I196N] 1, 4, 5 127 S241T Q194R I141A 15.58 [S253T] [Q206R] [I153A] 1, 4, 5 128 S241T Q194R I141T 14.16 [S253T] [Q206R] [I153T] 1, 4, 5 129 S241T Q194R I141H 56.73 [S253T] [Q206R] [I153H] 1, 4, 5 130 S241T D197K I141H 20.46 [S253T] [D209K] [I153H] 1, 4, 5 131 S241T D197K I141T 86.84 [S253T] [D209K] [I153T] 1, 4, 5 132 S241T D197K I141A 88.15 [S253T] [D209K] [I153A] 1, 4, 5 139 S241T D197K R146Q 21.81 [S253T] [D209K] [R158Q] 1, 4, 5 140 S241T D197K G147S 42.81 [S253T] [D209K] [G159S] 1, 4, 5 143 S241T D197K Q149T 49.33 [S253T] [D209K] [Q161T] 1, 4, 5 170 S241T Q194R R146A 39.74 [S253T] [Q206R] [R158A] 1, 4, 5 171 S241T Q194R R146Q 6.01 [S253T] [Q206R] [R158Q] 1, 4, 5 172 S241T Q194R G147S 1.49 [S253T] [Q206R] [G159S] 2, 4, 5 144 S241T D197K T152A 100.67 [S253T] [D209K] [T164A] 2, 4, 5 145 S241T D197K N150A 70.69 [S253T] [D209K] [N162A] 2, 4, 5 133 S241T Q194R T152R 17.46 [S253T] [Q206R] [T164R] 2, 4, 5 134 S241T D107K T152R 23.78 [S253T] [D209K] [T164R] 6, 4, 5 146 S241T D197K I321A 104.47 [S253T] [D209K] [I333A] 6, 4, 5 147 S241T D197K I321N 99.97 [S253T] [D209K] [I333N] 6, 4, 5 148 S241T D197K I321T 53.19 [S253T] [D209K] [I333T] 6, 4, 5 149 S241T D197K I321Q 99.91 [S253T] [D209K] [I333Q] 6, 4, 5 150 S241T D197K I321H 89.43 [S253T] [D209K [I333H] 6, 4, 5 152 S241T D197K Q326E 99.97 [S253T] [D209K] [Q338E] 3, 4, 5 173 S241T Q194R R192A 23.15 [S253T] [Q206R] [R204A] 3, 4, 5 174 S241T Q194R R192Q 16.37 [S253T] [Q206R] [R204Q] 3, 4, 5 175 S241T Q194R V189A 6.50 [S253T] [Q206R] [V201A] Quadruplicate Substitutions 1, 2, 4, 5 156 S241N Q194R I141T T152R 6.16 [S253N] [Q206R] [I153T] [T164R] 1, 2, 4, 5 166 S241N D197K I141A T152R 7.90 [S253N] [D209K] [I153A] [T164R] 1, 3, 4, 5 105 S241N D197K I184A I141A 0.00 [S253N] [D209K] [I196A] [I153A] 1, 3, 4, 5 106 S241K D197K I184A I141A 0.00 [S253K] [D209K] [I196A] [I153A] 1, 3, 4, 5 110 S241K D197K I184A I141T 0.00 [S253K] [D209K] [I196A] [I153T] 1, 3, 4, 5 111 S241P D197K I184A I141T 0.00 [S253P] [D209K] [I196A] [I153T] 1, 3, 4, 5 112 S241T D197K I184A I141T 0.00 [S253T] [D209K] [I196A) [I153T] 1, 3, 4, 5 114 S241K D197K I184A I141H 0.00 [S253K] [D209K] [I196A] [I153H] 1, 3, 4, 5 115 S241P D197K I184A I141H 0.00 [S253P] [D209K] [I196A] [I153H] 1, 3, 4, 5 117 S241N D197K I184N I141A 0.00 [S253N] [D209K] [I196N] [I153A] 1, 3, 4, 5 118 S241K D197K I184N I141A 0.00 [S253K] [D209K] [I196N] [I153A] 1, 3, 4, 5 120 S241T D197K I184N I141A 0.00 [S253T] [D209K] [I196N] [I153A] 1, 3, 4, 5 121 S241N D197K I184N I141T 0.00 [S253N] [D209K] [I196N] [I153T] 1, 3, 4, 5 122 S241K D197K I184N I141T 0.00 [S253K] [D209K] [I196N] [I153T] 1, 3, 4, 5 123 S241P D197K I184N I141T 0.00 [S253P] [D209K] [I196N] [I153T] 1, 3, 4, 5 124 S241T D197K I184N I141T 0.00 [S253T] [D209K] [I196N] [I153T] 1, 3, 4, 5 125 S241N D197K I184N I141H 0.00 [S253N] [D209K] [I196N] [I153H] 2, 3, 4, 5 179 S241T Q194R V189A T152R 13.37 [S253T] [Q206R] [V201A] [T164R] 2, 3, 4, 5 180 S241T Q194R R192A T152R 58.93 [S253T] [Q206R] [R204A] [T164R] 2, 3, 4, 5 181 S241T Q194R R192Q T152R 13.70 [S253T] [Q206R] [R204Q] [T164R] 1, 3, 4, 5 183 S241T D197K R192A I141A 36.87 [S253T] [D209K] [R204A] [I153A] 1, 3, 4, 5 188 S241T D197K R192A I141T 20.75 [S253T] [D209K] [R204A] [I153T] 1, 2, 4, 5 195 S241T D197K I141T T152A 42.90 [S253T] [D209K] [I153T] [T164A] 1, 4, 5, 6 200 S241T D197K I141T I321A 22.04 [S253T] [D209K] [I153T] [I333A] 1, 4, 5, 6 201 S241T D197K I141T I321N 58.30 [S253T] [D209K] [I153T] [I333N] 1, 4, 5, 6 204 S241T D197K I141T I321H 12.76 [S253T [D209K] [I153T] [I333H] 1, 2, 4, 5 208 S241T D197K I141A T152A 49.49 [S253T] [D209K] [I153A] [T164A] 1, 4, 5, 6 213 S241T D197K I141A I321A 18.03 [S253T] [D209K] [I153A] [I333A] 1, 4, 5, 6 214 S241T D197K I141A I321N 0.18 [S253T] [D209K] [I153A] [I333N] 1, 4, 5, 6 215 S241T D197K I141A I321T 5.87 [S253T] [D209K] [I153A] [I333T] 1, 4, 5, 6 216 S241T D197K I141A I321Q 20.21 [S253T] [D209K] [I153A] [I333Q] 1, 4, 5, 6 217 S241T D197K I141A I321H 11.22 [S253T] [D209K] [I153A] [I333H] 1, 4, 5, 6 219 S241T D197K I141A Q326E 70.65 [S253T] [D209K] [I153A] [Q338E] Quintuplicate Substitutions 222 S241T D197K G147S T152A Q326E 4.87 [S253T] [D209K] [G159S] [T164A] [Q338E] 224 S241T D197K Q149T T152A Q326E 3.69 [S253T] [D209K] [Q161T] [T164A] [Q338E] 226 S241T D197K I141A N150A Q326E 11.23 [S253T] [D209K] [I153A] [N162A] [Q338E] 1, 2, 4, 5, 6 228 S241T D197K I141A T152R Q326E 36.27 [S253T] [D209K] [I153A] [T164R] [Q338E] 1, 2, 4, 5, 6 229 S241T D197K I141A T152A Q326E 18.11 [S253T] [D209K] [I153A] [T164A] [Q338E] 1, 2, 3, 4, 5 221 S241T Q194R R192A I141A T152R 4.79 [S253T] [Q206R] [R204A] [I153A] [T164R] 1, 2, 4, 5, 6 242 S241T D197K I141T T152A Q326E 21.64 [S253T] [D209K] [I153T] [T164A] [Q338E] Sextuplicate Substitutions 1-6 244 S241T D197K R192A I141T T152A Q326E 20.53 [S253T] [D209K] [R204A] [I153T] [T164A] [Q338E] 1-6 246 S241T D197K R192A I141A T152A Q326E 7.95 [S253T] [D209K] [R204A] [I153A] [T164A] [Q338E] 1-6 248 S241T D197K R192A I141A T152R Q326E 4.45 [S253T] [D209K] [R204A] [I153A] [T164R] [Q338E] Note: Non-bracketed amino acid substitution positions correspond to the PE polypeptide sequence in SEQ ID NO: 1. Bracketed [amino acid substitution positions] correspond to the PE polypeptide sequence in SEQ ID NO: 2 (comprising an N-terminal 12-amino acid linker).

Example 11: Ex Vivo Human T Cell Assay to Assess Immunogenicity of Wild-Type (WT) and Amino Acid Substituted PE

Ex vivo human T cell assays (EPISCREEN™; see e.g., preceding Examples) were performed to assess the immunogenicity of whole proteins corresponding to pIEX02-244 (SEQ ID NO:178) pIEX02-246 (SEQ ID NO:179) and pIEX02-228 (SEQ ID NO:177) (Example 10). In order to avoid direct cytotoxicity to cells used in the assay, “null mutants” were generated for the three candidates and WT PE by overlapping PCR as in Example 9 using primers OL2162 and 2163 (Table 12) to introduce an amino acid substitution of E287D in the three candidates and WT PE (to give SEQ ID NOs: 180 to 183). (Note: “Null mutants” is intended to indicate mutated forms of PE which lack cell cytotoxic biological activity; the amino acid substitution used to generate null mutants corresponds to a change of E287D in SEQ ID NO:1 or E299 in SEQ ID NO:2.) The E287D (SEQ ID NOs: 180 to 183) encoding genes were cloned into pET14b-K as in Example 9. WT PE sequence is shown in SEQ ID NO:180; pIEX02-228 sequence is shown in SEQ ID NO:181; pIEX02-244 sequence is shown in SEQ ID NO:182; and, pIEX02-246 sequence is shown in SEQ ID NO:183. These were expressed as fusion proteins comprising a histidine polymer and a linker sequence preceding a “null mutant” sequence of WT PE or amino acid substituted PE; see, pIEX02-001 PE WT null mutant (SEQ ID NO:191 (DNA) and SEQ ID NO:192 (AA)), pIEX02-228 null mutant (SEQ ID NO:195 (DNA) and SEQ ID NO:196 (AA)), pIEX02-244 null mutant (SEQ ID NO:199 (DNA) and SEQ ID NO:200 (AA)), pIEX02-246 null mutant (SEQ ID NO:203 (DNA) and SEQ ID NO:204 (AA)).

The host cell for expression of the PE E287D genes was an Escherichia coli BL21 derivative strain called SHuffle™ T7 Express (NEB catalog #C3029H, New England Biolabs UK Ltd., Knowl Piece, UK) which was altered to overexpress the chaperonins GroEL/ES by amplification of the GroEL/ES operon, including its promoter/regulatory sites, from E. coli DH5alpha™ (Invitrogen catalog #18265-017, Life Technologies Ltd., Paisley, UK) using OL2097 (introducing EagI site) and OL2098, introducing HindIII site (Table 12). The resulting PCR fragment was subcloned into pACYC184 (NEB catalog #E4152S) which was then transformed into SHuffle™ T7 with selection for chloramphenicol resistance. The PE E287D (SEQ ID NOs: 180 to 183) genes in pET14b-K were transformed into the SHuffle™ T7/GroEL/ES strain with selection for ampicillin resistance. Single colonies were grown in 2×YT medium (Sigma-Aldrich catalog #Yr2627-1KG) and protein expression was induced at OD_(600 nm) 1.0 by adding isopropyl-β-D-thio-galactoside (IPTG) to a final concentration of 0.4 mM. Cultures were then grown at 16 degrees C. for 17 h before harvesting by centrifugation. Cell pellets were resuspended in 35 ml of binding buffer (50 mM Tris pH 8.0, 500 mM NaCl and 10 mM imidazole) supplemented with protease inhibitors (cOmplete protease inhibitor tablets, Roche catalog #11873580001, Roche Diagnostics Ltd., Burgess Hill, UK (mixture of several protease inhibitors for inhibition of serine and cysteine proteases)). Cells were lysed by sonication (SONICATOR®, Misonix catalog #XL2020, Misonix Inc., Farmingdale, N.Y.), and cell debris and insoluble material removed by centrifugation. Proteins were purified from the soluble fraction by nickel chelate affinity chromatography using HISTRAP® FF Crude columns (GE Healthcare catalog #11-004-58, GE Healthcare Life Sciences, Little Chalfont, UK). After loading, the columns were washed with 50 mM Tris (pH 8.0) containing 500 mM NaCl and 20 mM imidazole and bound protein was eluted with 50 mM Tris (pH 8.0) containing 500 mM NaCl and 500 mM imidazole. Following buffer exchange to 20 mM Tris (pH 8.0) using Zeba Spin desalting columns (7K MWCQ, Pierce catalog #89893), a negative purification step was employed using anion exchange chromatography on Q-Sepharose (1 ml, HISTRAP® Q FF column (GE Healthcare catalog #17-5053-01) with 20 mM Tris pH 8.0 and an NaCl gradient form 0 M to 1.5 M. For each protein, the column flow through was concentrated using an AMICON® Ultra centrifugal filter (EMD Millipore catalog #UFC 800 396, EMD Millipore, Feltham, UK) and further purified by size-exclusion chromatography (120 ml, HiLoad 16/60 SUPERDEX® 75 pg (GE Healthcare catalog #28-9893-33)) using 1×PBS pH 7.4 (PAA catalog #H15-002, PAA Laboratories Ltd, Yeovil, UK). For each protein, the protein peak was collected and concentrated.

Endotoxin levels were determined using an ENDOSAFE®-PTS™ Portable Test System reader (Charles River Laboratories Inc., Wilmington, Mass.) with ENDOSAFE® Licensed PTS Endotoxin cartridges (Charles River catalog #PTS20F). Endotoxins were reduced to a value below 5 endotoxin units (EU)/mg by repeatedly performing a phase separation using TritonX-114, (Aida Y. and Pabst M. J., Journal of Immunological Methods, 132 (1990) 191-195). Triton X-114 was removed using PIERCE® Detergent Removal Spin Columns according to the manufacturer's provided protocol (PIERCE® catalog #87779; Thermo Fisher Scientific/PIERCE® Biotechnology, Rockford, Ill.; see, Thermo Scientific Instructions manual #2164.3). Protein concentration was quantified by absorbance at 280 nm using a BIOMATE™ 3 UV-Visible spectrophotometer (Thermo Fisher Scientific) and a conversion factor of OD₂₈₀ 1.0=1.15 mg/ml derived from the calculated molar extinction coefficient of 6× His PE (Pace C. N. et al. Protein Science 1995 4:2411-2423).

Ex vivo human T cell assays (EPISCREEN®) were performed using PBMC isolated from healthy community donor buffy coats as in Example 2. A cohort of 20 donors was selected to best represent the number and frequency of HLA-DR allotypes expressed in the world population. The haplotypes of the 20 donors in the assay is shown in Table 14. PBMCs from each donor were thawed, counted and viability assessed. Cells were revived in room temperature AIM-V® culture medium (INVITROGEN®, Paisley, UK), washed and resuspended in AIM-V® to 4-6×10⁶ PBMC/ml. For each donor, 1 ml of cells were dispensed into multiple wells of a 24 well plate. 0.5 ml of proteins were added at 50 micrograms/ml per sample together with 0.5 ml of AIM-V® culture medium. For each donor, a reproducibility control (cells incubated with 100 micrograms/ml keyhole limpet hemocyanin (KLH), an “intermediate” positive control (expected to give 20-30% T cell responses) of humanized A33 antibody (Welt et al. Clinical Cancer Research, 9 (2003) p 1338-1343)(cells were incubated with 50 micrograms/ml humanized A33), and a culture medium only control well were also included. Cultures were incubated for a total of 8 days at 37° C. with 5% CO₂.

TABLE 14 Donor Haplotypes Donor KLH No Haplotype Test 1 IEX02 1 DRB1*01, DRB1*11; DRB3* 1.95 5.41 2 DRB1*11, DRB1*15; DRB3*; DRB5* N/D 8.39 3 DRB1*04, DRB1*11; DRB3*; DRB4* 6.04 4.58 4 DRB1*08, DRB1*14; DRB3* 1.78 1.35 5 DRB1*07, DRB1*13; DRB3*; DRB4* 5.57 6.77 6 DRB1*04; DRB4* 12.36 11.25 7 DRB1*03, DRB1*04; DRB3*; DRB4* 1.48 1.12 8 DRB1*03, DRB1*13; DRB3* 2.73 1.63 9 DRB1*03, DRB1*07; DRB3*; DRB4* 3.59 3.07 10 DRB1*04, DRB1*12; DRB3*; DRB4* 3.35 3.26 11 DRB1*01, DRB1*07 13.67 15.34 12 DRB1*01, DRB1*14; DRB3* 6.05 50.13 13 DRB1*07, DRB1*09; DRB4* 9.17 19.32 14 DRB1*15; DRB5* 2.83 3.97 15 DRB1*03, DRB1*15; DRB3*; DRB5* 3.36 3.09 16 DRB1*07, DRB1*13; DRB3*; DRB4* 2.18 6.76 17 DRB1*15, DRB1*13, DRB3*; DRB5* 1.93 7.04 18 DRB1*01, DRB1*04; DRB4* 2.49 28.59 19 DRB1*01, DRB1*11; DRB3* 0.83 4.50 20 DRB1*01 2.03 3.18

For the T cell proliferation assay, on days 5, 6, 7 and 8, the cells in each well were gently resuspended and triplicate 100 microliter aliquots were transferred to each well of a round bottomed 96 well plate. The cultures were pulsed with 0.75 microCi [3H]-Thymidine (PERKIN ELMER®, Beaconsfield, UK) in 100 microliters AIM-V® culture medium and incubated for a further 18 hours before harvesting onto filter mats (Perkin Elmer®) using a TOMTEC® HARVESTER 96™ Mach III cell harvester (TOMTEC® Inc., Hamden, Conn., USA). Counts per minute (cpm) for each well were determined using MELTILEX® solid scintillator (PERKIN ELMER® Life and Analytical Sciences, Shelton, Conn., USA) via scintillation counting on a Wallac 1450 Microbeta Trilux Microplate Scintillation and Luminescence Counter (Perkin Elmer®) in paralux, low background counting.

For proliferation assays, an empirical Stimulation Index (S) threshold of equal to, or greater than, 2 (SI≧2.0) was used whereby samples inducing proliferative responses above this threshold at any day after addition of protein were deemed positive. (The Stimulation Index is a ratio of stimulated proliferative response compared to a background index; an SI of 1=background or “noise”.) For the triplicate proliferation data for each time point with each protein, the significance (p<0.05) of positive responses was defined by statistical and empirical thresholds by comparing CPM of test protein wells against medium-only control wells using unpaired two sample Student's T-Test.

The results of the proliferation assay are shown in Table 15. The results demonstrate a significantly reduced level of T cell responses from the amino acid substituted PE molecules: pIEX02-228 (SEQ ID NO:181) 5% donor responses; pIEX02-244 (SEQ ID NO:182) 10% donor responses; and, pIEX02-246 (SEQ ID NO:183) 20% donor responses, compared to WT PE (SEQ ID NO:180) which induced T cell responses in 70% of donors.

TABLE 15 Relative T-cell Stimullated Proliferative Responses to Amino Acid Substituted variants of PE compared to Wild-Type (WT) PE. WT pIEX02- pIEX02- pIEX02- Hu PE 228 244 246 A33 Donor 1 P Donor 2  P* P Donor 3  P* P P P Donor 4 Donor 5 Donor 6 P Donor 7 Donor 8 P Donor 9 P Donor 10 P Donor 11 P P P Donor 12 P P Donor 13 P Donor 14 P P P Donor 15 P Donor 16 P P Donor 17 P Donor 18 Donor 19 P P P Donor 20 % Donor 70 5 10 20 30 Proliferation *Positive T cell responses for proliferation (SI ≧ 2.00, significant p < 0.05) during the entire time course days 5-8 (“P”) are shown. **Borderline responses (significant p < 0.05 with SI ≧ 1.90) are shown (*).

In addition to the proliferation assay, additional analysis of the cytokines IL-2 and IL-6 was performed using aliquots of culture supernatant taken on day 6. The analysis was performed using the BD Cytometric Bead Array (CBA) Enhanced Sensitivity Flex Set Systems for IL-2 and IL-6 (BD Bioscience, Oxford, UK) according to the manufacturer's instructions. The enhanced sensitivity standards from the CBA kit were reconstituted and serially diluted before adding 50 microliters of supernatant or standard to 20 microliters of mixed capture beads in 96 well filter plates (Millipore, Watford, UK) and incubating for 2 hours. Mixed human detection reagent (20 microliters) was then added to each well and incubated for a further 2 hours. Plates were washed twice and enhanced detection (100 microliters) reagent added to each well for a final 1 hour incubation. Plates were washed before reading on an Accuri C6 instrument (BD Biosciences).

Data was analysed using FCAP v3.0 software (BD Biosciences). For each individual donor, data was expressed as pg/ml of cytokine for each donor and plotted on a log scale with a median of cytokine levels depicted as a line. The results are shown in FIG. 11 which shows a significantly reduced level of the cytokines IL-2 and IL-6 from the amino acid substituted PE molecules pIEX02-228 (SEQ ID NO:181), pIEX02-244 (SEQ ID NO:182) and pIEX02-246 (SEQ ID NO:183) compared to WT PE (SEQ ID NO:180).

The proliferation and cytokine results both independently demonstrate that the amino acid substitutions in PE result in greatly reduced level of T cell responses when using amino acid substituted forms of PE. These results considered and expected to correlate with low or reduced PE immunogenicity in human subjects.

Example 12: Cytotoxicity Analysis of Amino Acid Substituted PE in Dendritic Cells

Amino acid substituted forms of PE and WT PE may be generated as in Example 11. For a dendritic cell cytotoxicity assay, PBMC are isolated from healthy community donor buffy coats (preferably from blood drawn within 24 hours), for example, by Lymphoprep (Axis-shield, Dundee, UK) density centrifugation. To prepare monocyte-derived dendritic cells (DC), CD14+ cells (monocytes) may be isolated from donor PBMC preparations using Miltenyi Monocyte Isolation Kit II (human) and LS columns (Miltenyi Biotech GmbH, Bergisch Gladbach, Germany, catalog #130-091-153). Monocytes are resuspended in an appropriate culture medium, such as AIM-V® cell culture medium supplemented with 1000 IU/ml IL-4 and 1000 IU/ml GM-CSF (“DC culture medium”) to 4-6×10⁶ cells/ml and then distributed in 24 well plates (e.g., 2 ml final culture volume). Cells are fed on day 2 by half volume DC culture medium change. On day 3, amino acid substituted PE and WT PE proteins are added to semi-mature DC to selected final concentrations, such as 1 micrograms/ml or 10 micrograms/ml. Semi-mature DC are incubated for a period of time, such as 24-72 hours, after which cells are assessed for cytotoxicity by viability, such as via use of Trypan Blue (Sigma, Dorset, UK) dye exclusion and by propidium iodide (PI) and Annexin V staining (Invitrogen, Paisley UK) followed by FACS analysis.

Example 13: Cytotoxicity Analysis of Anti-CD22 scFv Fused to Amino Acid Substituted PE in RAJI Cells

WT PE and amino acid substituted PE encoded by pIEX02-244 (SEQ ID NO:178) are fused to an anti-CD22 single-chain Fv (scFv). The VH and VL (V_(kappa)) regions of RFB4 (Campana D. et al., J. Immunol., 134:1524-1530 (1985); Mansfield, E, et al., Blood, 90:2020-2026 (1997) are synthesized. RFB4 VH is amplified using oligonucleotides: OL2043 and OL2044 (Table 12). RFB4 and VL (Vk) is amplified using oligonucleotides OL2045 and OL2046 (Table 12). The RFB4 scFv is obtained using a pull-through PCR reaction using oligonucleotides OL2047 introducing a NcoI site and OL2048 introducing a XhoI site. The resultant PCR product is subcloned into pET14b-K via NcoI and XhoI restriction enzymes (Fermentas catalog #FD0573 and FD0695, respectively).

The gene encoding RFB4 scFv is fused to genes encoding either WT PE or amino acid substituted PE encoded by pIEX02-244 (SEQ ID NO:178) having a C-terminal 8× His-tag followed by the sorting signal EDLK to give fusion sequences SEQ ID NO:184 and SEQ ID NO:186, respectively, which are cloned into the expression vector pET14b-K by fusion PCR. To create these RFB4-PE fusions a fusion PCR is carried out. The RFB4 scFv gene is amplified from pET14b-RFB4 using oligonucleotides OL2318 introducing a NcoI site and OL2320 (Table 12). The WT PE or the lead amino acid substituted PE genes are amplified from pET14b-K-WT PE or pET14b-K-244 PE, respectively, using oligonucleotides OL2321 and OL2322 introducing a N-terminal 8× His-EDLK and a XhoI site (Table 12). Both scFv and PE genes are fused by performing a PCR with oligonucleotides OL2318 and OL2322 (Table 12). The resulting full-length fragments are subcloned into pET14b-K using NcoI and XhoI restriction enzymes. Plasmids are transformed into BL21(DE3) E. coli (EMD Millipore, Feltham, UK) and clones are inoculated into 2TY+Amp and grown overnight at 37° C. Two ml of overnight culture is inoculated into 350 ml 2TY+Amp media in a 1 L flask and grown to OD_(600 nm)=1 before addition of IPTG (Sigma) to 1 mM (final concentration). Cultures are grown overnight at 30 degrees C. overnight and centrifuged at 10000 rpm. Bacterial pellets are frozen at −80 until ready to use.

Pellets are defrosted on ice, extracted with 10 ml B-PER® Bacterial Protein Extraction Reagent (PIERCE® Biotechnology, Rockford, Ill.; Thermo Scientific, Hemel Hempstead, UK) containing Lysozyme and DNaseI (both Thermo Scientific), and rotated for 1 hour at room temperature. Samples are then centrifuged at 10000 rpm and supernatants are discarded. Each pellet is resuspended in 5 ml B-PER containing Lysozyme and DNaseI as above and extracted for an additional 30 min at room temperature. After centrifugation, pellets are pooled and washed successively with Wash Buffer A (50 mM Tris-HCl pH 8.0, 100 mM NaCl, 1 mM EDTA, 0.5 M urea and 1.0% Triton X-100), Wash Buffer B (Buffer A but without urea), and twice with Wash Buffer C (Buffer A but without urea or Triton X-100). After final wash, insoluble pellets are stored at −80° C. cOmplete® mini-EDTA protease inhibitors (Roche Diagnostics Ltd.) are included at each step.

Pellets are resuspended in 10 ml Solubilisation Buffer (50 mM Tris-HCl pH 8.0, 100 mM: NaCl, 8 M Urea and 1 mM DTT). OD_(280 nm) is determined and the samples are diluted to approximately 1 mg/ml in Solubilisation Buffer. Protein samples are allowed to denature for 4 hours at room temperature and centrifuged at 10000 rpm to remove insoluble debris, 10 ml of each solubilised protein samples is injected into a pre-soaked 12 ml, 3K MWCO cut-off SLIDE-A-LYSER® Dialysis Cassette dialysis device (Thermo Scientific; PIERCE® Biotechnology, Inc., IL, USA), and dialyzed by placement overnight in a beaker containing 2.5 L Refolding Buffer A (50 mM Tris HCl pH 8.0, 100 mM NaCl, 5 mM reduced glutathione, 1 mM oxidised glutathione, 0.1 M arginine, 4 M urea). Dialysis buffer is replaced with, in order, 2.5 L Refolding Buffer B (Buffer A with 2 M urea), 2.5 L Refolding Buffer C (Buffer A with 1 M urea) and 5 L Refolding Buffer D (Buffer A without urea or arginine) for a minimum of 4 hours at each step.

Each sample is recovered from the dialysis cassette, buffer exchanged into 50 mM 2-N-morpholino)ethanesulfonic acid (MES) pH 6.2 using PD10 desalting columns (GE Healthcare, Little Chalfont, UK) and loaded onto a 1 ml SP FF Anion Exchange column (GE Healthcare). Each column is washed with 50 mM MES pH 6.2 before during using a linear 0M to 1M NaCl gradient in 50 mM MES pH6.2. Protein-containing fractions are pooled and run through a pre-equilibrated 16/60 Size Exclusion column (GE Healthcare) using 1×PBS as running buffer. Fractions containing the main protein peaks are collected, pooled and concentrated to approximately 1 ml, filter sterilized and quantified.

For cytotoxicity analysis, Raji cells (ATCC, CCL-86) are propagated in growth medium (RPMI-1640, 10% FBS, 1% Pen/Strep) and harvested during mid-log growth phase. Cells are diluted to 1×10⁵ cells/ml in growth medium and 50 microliter aliquots are dispensed per well in white wailed, clear bottom 96 well plates (CORNING® catalogue #3610, FISHER SCIENTIFIC®, Loughborough, UK). Each protein concentration (8×4-fold dilutions from 500 nanograms/ml) is tested in triplicate wells, and controls containing cells or growth medium only are also included. Test protein is diluted to 2× desired concentration in growth medium. 50 microliters of the test protein dilutions or controls are added to the Raji cells and plates are incubated 72 hrs in a humidified cell culture incubator (37° C., 5% CO₂). After incubation, plates are equilibrated at room temperature for 10 min. CELLTITER-GLO® (PROMEGA® catalogue #G7571) is prepared according to manufacturer's instructions and 100 microliters is added per well. Plates are incubated for 10 min before reading via a FLUOstar OPTIMA fluorescence plate reader (BMG Labtech Ltd., Aylesbury, UK) (also known as a fluorometer).

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The invention claimed is:
 1. A polypeptide having at least one Pseudomonas exotoxin A (PE-A) biological activity, wherein said polypeptide comprises one or more amino acid substitutions compared to a wild-type PE-A polypeptide, wherein said one or more amino acid substitutions is a substitution of a different amino acid at one or more positions corresponding to amino acid residues in the polypeptide of SEQ ID NO:1, wherein one of said substitutions is selected from the group consisting of: a) glycine (G) at position 147 is substituted with an aliphatic amino acid residue; and, b) glycine (G) at position 147 is substituted with alanine (A), serine (S), or threonine (T).
 2. The polypeptide of claim 1, wherein the different aliphatic amino acid residue substitution for glycine (G) at position 147 is alanine (A), valine (V), leucine (L), or isoleucine (I).
 3. The polypeptide of claim 1, wherein the substitution for glycine (G) at position 147 is alanine (A).
 4. The polypeptide of claim 1, wherein the at least one Pseudomonas exotoxin A (PE-A) biological activity comprises the ability to inhibit in vitro transcription/translation compared to a corresponding wild-type or non-substituted PE-A polypeptide, wherein said ability to inhibit in vitro transcription/translation is in an amount selected from the group consisting of: a) at least 5% inhibition; b) at least 10% inhibition; c) at least 15% inhibition; d) at least 20% inhibition; e) at least 25% inhibition; f) at least 30% inhibition; g) at least 40% inhibition; h) at least 50% inhibition; i) at least 60% inhibition; j) at least 70% inhibition; k) at least 80% inhibition; l) at least 90% inhibition; m) at least 100% inhibition; n) about 100% inhibition; and o) 100% inhibition.
 5. The polypeptide of claim 1, wherein said polypeptide comprises one or more amino acid substitutions which prevent or reduce host immunogenic responses compared to the same polypeptide without said one or more amino acid substitutions.
 6. The polypeptide of claim 1, wherein the last five or six amino acids in said polypeptide comprise one or more amino acid sequences selected from the group consisting of: a) Arg-Glu-Asp-Leu-Lys; b) Arg-Glu-Asp-Leu; c) Lys-Asp-Glu-Leu; d) Glu-Asp-Leu-Lys; and e) a dimer, trimer, pentamer, hexamer, septamer, or octamer of (i), (ii), or (iii), or any combination thereof.
 7. The polypeptide of claim 1, wherein said polypeptide has one or more biological activities selected from the group consisting of: a) eukaryotic cell killing activity (cell cytotoxicity); b) inhibits translation elongation factor EF-2 biological activity; c) induces or catalyzes ADP-ribosylation of EF-2; and d) inhibits protein synthesis.
 8. The polypeptide of claim 1, wherein said one or more amino acid substitutions reduce host immunogenic responses compared to a polypeptide comprising an amino acid sequence selected from the group consisting of: a) SEQ ID NO:1; b) SEQ ID NO:4; c) SEQ ID NO:133; and d) SEQ ID NO:134.
 9. The polypeptide of claim 1, wherein said polypeptide is a fusion protein.
 10. A polynucleotide encoding the polypeptide of claim
 1. 11. An expression vector comprising the polynucleotide of claim
 10. 12. A host cell comprising the expression vector of claim
 11. 13. A polynucleotide encoding the fusion protein of claim
 9. 14. The polypeptide of claim 1, wherein said polypeptide is a fusion protein.
 15. The polypeptide of claim 3, wherein said polypeptide is a fusion protein.
 16. A polynucleotide encoding the polypeptide of claim
 1. 17. A polynucleotide encoding the polypeptide of claim
 3. 18. A polynucleotide encoding the fusion protein of claim
 14. 19. A polynucleotide encoding the fusion protein of claim
 15. 20. An expression vector comprising the polynucleotide of claim
 16. 21. An expression vector comprising the polynucleotide of claim
 17. 22. A host cell comprising the expression vector of claim
 20. 23. A host cell comprising the expression vector of claim
 21. 